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Showing posts with label children. Show all posts
Showing posts with label children. Show all posts

Tuesday, December 29, 2015

POLIO VACCINATION / IPV / OPV or Oral Polio Vaccines has not been used in the USA since 2000

Polio Vaccination is highly recommended with Inactivated Polio Vaccine. Parenteral Polio Vaccination. OPV or Oral Polio Vaccines has not been used in the United States since 2000. OPV or Oral Polio Vaccines is used worldwide!

Carlos E Mijares, MD Allergist / Immunologist, pediatrician.

Vaccines and Immunizations

Polio Vaccination

Pronounced [PO-lee-oh]

At a Glance

Polio vaccination Polio is an infectious disease caused by a virus that lives in the throat and intestinal tract. It is most often spread through person-to-person contact with the stool of an infected person and may also be spread through oral/nasal secretions. Polio used to be very common in the United States and caused severe illness in thousands of people each year before polio vaccine was introduced in 1955. Most people infected with the polio virus have no symptoms; however, for the less than 1% who develop paralysis it may result in permanent disability and even death.
There are two types of vaccine that protect against polio: inactivated poliovirus vaccine (IPV) and oral poliovirus vaccine (OPV). IPV is given as an injection in the leg or arm, depending on the patient's age. Polio vaccine may be given at the same time as other vaccines. Most people should get polio vaccine when they are children. Children get 4 doses of IPV at these ages: 2 months, 4 months, 6-18 months, and a booster dose at 4-6 years. OPV has not been used in the United States since 2000 but is still used in many parts of the world.

What You Should Know

About the Disease

Vaccine Information

A person is considered to be fully immunized if he or she has received a primary series of at least three doses of inactivated poliovirus vaccine (IPV), live oral poliovirus vaccine (OPV), or four doses of any combination of IPV and OPV. Until recently, the benefits of OPV use (i.e. intestinal immunity, secondary spread) outweighed the risk for vaccine-associated paralytic poliomyelitis (VAPP) which occurred in one child out of every 2.4 million OPV doses distributed. To eliminate the risk of vaccine-associated paralytic poliomyelitis (VAPP), as of January 1, 2000, OPV was no longer recommended for routine immunization in the United States. However, OPV continues to be used in the countries where polio is endemic or the risk of importation and transmission is high. OPV is recommended for global polio eradication activities in polio-endemic countries due to its advantages over IPV in providing intestinal immunity and providing secondary spread of the vaccine to unprotected contacts.

Beliefs & Concerns

Vaccine Safety

As with all vaccines, there can be minor reactions, including pain and redness at the injection site, headache, fatigue or a vague feeling of discomfort.

Who Should Not be Vaccinated?

For Health Professionals

Clinical Information on Polio

Vaccine Recommendations

References and Resources

Materials for Patients


Global Initiatives

Global Polio Eradication


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Sunday, December 27, 2015

PARASITIC MENINGOENCEPHALITIS / CONTAMINATED WATER AND SWIMMING







Parasitic Meningitis


Causes

Primary amebic meningoencephalitis (PAM) is a very rare form of parasitic meningitis that causes a brain infection that is usually fatal. The parasite enters the body through the nose and is caused by the microscopic ameba (a single-celled living organism) Naegleria fowleri.

Risk Factors

Naegleria fowleri is found around the world. In the United States, the majority of infections have been caused by Naegleria fowleri from warm freshwater located in southern-tier states.1 The ameba can be found in:
  • Bodies of warm freshwater, such as lakes and rivers
  • Geothermal (naturally hot) water, such as hot springs
  • Warm water discharge from industrial plants
  • Geothermal (naturally hot) drinking water sources
  • Swimming pools that are poorly maintained, minimally-chlorinated, and/or un-chlorinated
  • Water heaters. Naegleria fowleri grows best at higher temperatures up to 115°F (46°C) and can survive for short periods at higher temperatures.2, 3
  • Soil
Naegleria fowleri is not found in salt water, like the ocean.

Transmission

Naegleria fowleri infects people by entering the body through the nose. This typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers.1 The Naegleria fowleri ameba travels up the nose to the brain where it destroys the brain tissue.
You cannot be infected with Naegleria fowleri by drinking contaminated water. In very rare instances, Naegleria infections may also occur when contaminated water from other sources (such as inadequately chlorinated swimming pool water or contaminated tap water) enters the nose, for example when people submerge their heads or cleanse their noses during religious practices4, 5, and when people irrigate their sinuses (nose) using contaminated tap water6.
The Naegleria fowleri ameba causes primary amebic meningoencephalitis (PAM) when it travels up the nose to the brain and destroys the brain tissue.Naegleria fowleri infections are very rare. In the 10 years from 2003 to 2012, 31 infections were reported in the U.S. All were fatal.
PAM cannot be spread from one person to another.
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Signs and Symptoms

Naegleria fowleri causes the disease primary amebic meningoencephalitis (PAM), a brain infection that leads to the destruction of brain tissue. In its early stages, symptoms of PAM may be similar to symptoms of bacterial meningitis.
Initial symptoms of PAM start 1 to 7 days after infection. The initial symptoms include headache, fever, nausea, vomiting, and stiff neck. Later symptoms include confusion, lack of attention to people and surroundings, loss of balance, seizures, and hallucinations. After the start of symptoms, the disease progresses rapidly and usually causes death within about 5 days (range 1 to 12 days).

Diagnosis

PAM is rare. The early symptoms of PAM are more likely to be caused by other more common illnesses, such as bacterial or viral meningitis. People should seek medical care immediately whenever they develop a sudden onset of fever, headache, stiff neck, and vomiting, particularly if they have been in warm freshwater recently.

Treatment

Several drugs are effective against Naegleria fowleri in the laboratory. However, their effectiveness is unclear since almost all infections have been fatal, even when people were treated.
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Prevention

Naegleria fowleri infects people when water containing the ameba enters the body through the nose. Infection is rare and typically occurs when people go swimming or diving in warm freshwater places, like lakes and rivers. Very rarely, infections have been reported when people submerge their heads, cleanse their noses during religious practices, or irrigate their sinuses (nose) using contaminated tap or faucet water. Naegleria fowleri can grow in pipes, hot water heaters, and water systems, including treated public drinking water systems.
Personal actions to reduce the risk of Naegleria fowleri infection should focus on limiting the amount of water going up the nose and lowering the chances that Naegleria fowleri may be in the water.
Please visit the following pages for information on lowering your risk of infection in specific situations:

References

  1. Yoder JS, Eddy BA, Visvesvara GS, Capewell L, Beach MJ. The epidemiology of primary amoebic meningoencephalitis in the USA, 1962-2008.Epidemiol Infect. 2010;138:968-75.
  2. Griffin JL. Temperature tolerance of pathogenic and nonpathogenic free-living amoebas. Science. 1972;178(63):869-70.
  3. Stevens AR, Tyndall RL, Coutant CC, Willaert E. Isolation of the Etiological Agent of Primary Amoebic Meningoencephalitis from Artificially Heated Waters. Appl Environ Microbiol. 1977;34(6):701-705.
  4. CDC. Primary amebic meningoencephalitis associated with ritual nasal rinsing — St. Thomas, U.S. Virgin Islands, 2012. MMWR Morb Mortal Wkly Rep. 2013;62(45):903.
  5. Shakoor S, Beg MA, Mahmood SF, Bandea R, Sriram R, Noman F, et al. Primary amebic meningoencephalitis caused by Naegleria fowleri, Karachi, Pakistan.[PDF - 4 pages] Emerg Infect Dis. 2011:17;258-61.
  6. Yoder JS, Straif-Bourgeois S, Roy SL, Moore TA, Visvesvara GS, Ratard RC, Hill V, Wilson JD, Linscott AJ, Crager R, Kozak NA, Sriram R, Narayanan J, Mull B, Kahler AM, Schneeberger C, da Silva AJ, Beach MJ. Deaths from Naegleria fowleri associated with sinus irrigation with tap water: a review of the changing epidemiology of primary amebic meningoencephalitis. Clin Infect Dis. 2012;1-7.
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Related Page




Tuesday, December 22, 2015

FLU VACCINE for All: A Critical Look at the Evidence

Of note, Immunization, Obesity, Illiteracy and High School drop out are actual priorities worldwide!

Allergy & Clinical Immunology

Flu Vaccine for All: A Critical Look at the Evidence

Eric A. Biondi, MD, MS; C. Andrew Aligne, MD, MPH
Disclosures | December 21, 2015

When Vaccination Became Routine

Vaccine proponents felt that the failure of the vaccine was explained by the immunization campaign being too little, too late. As a result, in 1960, national health experts recommended, for the first time, routine annual vaccination, with emphasis on high-risk groups, including those over the age of 65 years and individuals with chronic illness.[13] By the early 1960s, routine influenza vaccination was generally adopted as a policy, with very little supporting evidence.
After several years of this policy, the CDC decided to evaluate its impact. In 1964, Alexander Langmuir, MD, MPH, then the chief epidemiologist at the CDC, published a paper[13] that "reluctantly concluded that there is little progress to be reported. The severity of the epidemic of 1962-1963...demonstrates the failure to achieve effective control of excess mortality." The paper questioned whether widespread influenza immunization "should be continued without better evidence to justify the major costs to the general public." Despite this, annual vaccination campaigns were continued.
In 1968, the CDC finally performed a randomized, double-blind trial[14] to examine the effect of vaccination on morbidity and mortality. The authors concluded that "Despite extensive use of influenza vaccines...attainment of [improved morbidity and mortality] has never been demonstrated." Nevertheless, flu immunization continued.
In 1976, H1N1 "swine flu" appeared, and a large-scale effort to immunize as many Americans as possible was launched.[15] However, the anticipated levels of disease did not appear, and an epidemic of paralytic Guillain-Barré syndrome in recipients of vaccine led to the program's cancellation. An analysis in 1977[16] by the CDC concluded that influenza control had been "generally ineffective" and that statistically valid community trials were needed.
In 1995, a major review from the US Food and Drug Administration acknowledged the ongoing "paucity of randomized trials" and warned about serious methodological flaws in many existing flu vaccine studies.[17]
In 2000, the CDC performed a placebo-controlled trial and found that "vaccination [when compared to placebo] may not provide overall economic benefit in most years."[18]
Nonetheless, in 2004, the AAP recommended annual influenza immunization for young children, household contacts, and healthcare providers.[19]
Vaccination coverage recommendations continued to expand, and now during every flu season, we watch commercials by retail pharmacies telling us about the importance of getting the flu shot. The fact that the AAP recommends "mandatory" flu vaccination for healthcare providers[20] means that eventually clinicians could be fired for not getting vaccinated.

Summing Up the Data

A 2012 systematic review and meta-analysis[21] examined the efficacy and effectiveness of licensed influenza vaccines in patients with confirmed influenza illness. The authors confirmed that the original "recommendation to vaccinate the elderly was made without data for vaccine efficacy or effectiveness." The main message was that we need a better vaccine and better studies to demonstrate its effectiveness.
Despite the lack of high-quality data supporting the value of the flu shot, widespread vaccination policy might still be reasonable if observational studies consistently showed a benefit. However, the observational studies cited by flu shot proponents are frequently flawed.[22-28] In many studies, relevant clinical outcomes are ignored in favor of immunogenicity (ie, the ability to elicit an antibody response). "Influenza-like illness" (ie, cold symptoms) is frequently measured instead of serious outcomes, such as pneumonia or death. When these more serious outcomes are examined, there is often a failure to control for healthy user bias—the propensity for healthier people to do such things as receive annual check-ups, eat healthier foods, and get the flu shot. So, although it's true that people who get flu shots live longer, it may have nothing to do with actually getting the flu shot.
A 2005 study of a 33-season, national data set attempted to reconcile the reduced all-cause morbidity and mortality found in some observational studies of influenza vaccination with the fact that "national influenza mortality rates among seniors increased in the 1980s and 1990s as the senior vaccination coverage quadrupled."[29] In this study, the authors conclude that:
"[Our] estimates, which provide the best available national estimates of the fraction of all winter deaths that are specifically attributable to influenza, show that the observational studies must overstate the mortality benefits of the vaccine...[even during two pandemic seasons] the estimated influenza-related mortality was probably very close to what would have occurred had no vaccine been available."
The rationale for flu immunization as a national health priority is that influenza is a disease with serious complications, such as pneumonia, hospitalization, and death.[5,13,28] If the reason for influenza vaccination is that flu is such a serious disease, then the relevant outcomes are whether vaccination improves morbidity and mortality from flu. However, after decades of vaccine use, it is hard to detect any public health impact. This is in stark contrast to other routine vaccinations, such as polio and Haemophilus influenzae type b, where introduction of the vaccine led to obvious decline of the disease.
We are pediatricians, and we believe in childhood immunizations. Many vaccines have provided immense public health value. We simply question whether the policy of routine influenza vaccination has outpaced the data supporting its use.
Influenza vaccination now supersedes many other priorities of public health (such as obesity, illiteracy, and high school dropout), and we question whether so much time, effort, and money should be dedicated to flu vaccination while these other national healthcare priorities remain on the back burner.
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Friday, December 11, 2015

HUMAN PAPILLOMA VIRUS VACCINES / VACUNAS CONTRA EL VPH



Bienvenido, Biblioteca Centro Medico Caracas
Recommendations for the use of human papillomavirus vaccines
Recommendations for the use of human papillomavirus vaccines
Disclosures: Philip E Castle, PhD, MPH Speaker’s Bureau: Roche Molecular Systems [cervical cancer (Cobas HPV test)]; Cepheid [cervical cancer (GeneXpert HPV test)]. Consultant/Advisory Boards: Roche [HPV testing (Cobas HPV test)]; Cepheid [cervical cancer (GeneXpert HPV test)]; Teva Pharmaceuticals [HPV therapeutics]; Genticel [HPV testing]; ClearPath [HPV testing]; Guided Therapeutics [HPV testing]; Hologic [HPV testing (Aptima HPV Test)]; GE Healthcare [Sample prep (FTA Elute-specimen transport medium)]. Data and Safety Monitoring Board: Merck [cervical cancer (Gardasil and Gardasil 9 HPV vaccines)]. J Thomas Cox, MD Speaker's Bureau: Roche [HPV testing (HPV test)]; Hologic/Gen-Probe [HPV testing (HPV test)]. Consultant/Advisory Boards: Merck [Data safety and monitoring board (Quadrivalent and nonavalent HPV vaccine)]; Roche [Advisory board (HPV test)]; Hologic/Gen-Probe [Advisory board (HPV test)]; Trovagene [Scientific advisory board (Urine HPV test)]; Zilico [Advisory board (Optical spectroscopy as a colposcopy adjunct)]. Joel M Palefsky, MD Grant/Research/Clinical Trial Support: Merck and Co [HPV infection (Quadrivalent and nonavalent HPV vaccines)]; Hologic [HPV infection (HPV assay)]. Consultant/Advisory Boards: Merck [HPV infection (Quadrivalent and nonavalent HPV vaccines)]; TheVax [HPV infection (therapeutic HPV vaccine)]; Antiva Biosciences [HPV infection (HPV therapeutics)]. Martin S Hirsch, MD Nothing to disclose. Allyson Bloom, MD Nothing to disclose.
Contributor disclosures are reviewed for conflicts of interest by the editorial group. When found, these are addressed by vetting through a multi-level review process, and through requirements for references to be provided to support the content. Appropriately referenced content is required of all authors and must conform to UpToDate standards of evidence.
All topics are updated as new evidence becomes available and our peer review process is complete.
Literature review current through: Nov 2015. | This topic last updated: Dec 10, 2015.
INTRODUCTION — Human papillomavirus is a sexually transmitted pathogen that causes anogenital disease in males and females. Persistent viral infection with high-risk human papillomavirus (HPV) genotypes causes virtually all cancers of the cervix. The same HPV genotypes (or "types") that cause cancer of the cervix also cause most cases of anal cancer [1] and significant proportion of oropharyngeal cancer in men and women, a significant proportion of vulvar and vaginal cancer, and significant proportion of penile cancer. Three vaccines have been developed against HPV infection; one is a quadrivalent vaccine (Gardasil), one is 9-valent (Gardasil 9), and the other is a bivalent vaccine (Cervarix).
This topic will cover issues related to routine immunization recommendations, vaccination in special patient populations, and vaccine safety. The natural history, details on epidemiology, and immunology of HPV infection, as well as clinical trial data on HPV vaccines are discussed elsewhere. (See "Epidemiology of human papillomavirus infections" and "Clinical trials of human papillomavirus vaccines" and "The life cycle, natural history, and immunology of human papillomaviruses".)
DISEASE ASSOCIATIONS
HPV-related disease in females
Cervical cancer and precursor lesions — Cervical cancer is the third most common female cancer worldwide, with an estimated incidence of 530,000 and 270,000 related deaths in 2012; the attributable fraction due to HPV infection was estimated to be 100 percent [2,3]. HPV types 16 and 18 cause approximately 70 percent of cervical cancers and 50 percent of precancerous cervical lesions (ie, cervical intraepithelial neoplasia grade 2 and grade 3 [CIN2/3]). HPV types 31, 33, 45, 52, and 58 are estimated to cause an additional 19 percent of invasive cervical cancers [4]. The estimated annual incidence in the United States of CIN among females who undergo cervical cancer screening is 0.4 percent for CIN 1 and 0.5 percent for CIN 2/3 [5]. (See "Invasive cervical cancer: Epidemiology, risk factors, clinical manifestations, and diagnosis" and "Cervical intraepithelial neoplasia: Terminology, incidence, pathogenesis, and prevention", section on 'Incidence'.)
Vulvar and vaginal cancer and precursor lesions — Vulvar and vaginal cancer are rare cancers globally, with an estimated incidence of 27,000 vulvar cancers and 13,000 vaginal cancers in 2008; the attributable fraction due to HPV infection has been estimated to be 43 percent for vulvar cancer and 70 percent for vaginal cancer [2]. Other data have suggested that only 29 percent of vulvar cancers are HPV positive whereas 87 percent of vulvar intraepithelial neoplasia (VIN) are HPV positive [6]. HPV 16 and HPV 18 cause approximately 60 percent of HPV-positive vaginal cancers and precancerous vaginal lesions; HPV 16 and HPV 18 cause approximately 35 to 77 percent of HPV-positive vulvar cancers and 75 to 80 percent of precancerous vulvar lesions [6,7]. (See "Vaginal cancer" and "Vulvar intraepithelial neoplasia".)
HPV-related disease in females and males
Anal cancer and precursor lesions — Anal cancer is a rare cancer globally, with an estimated incidence of 27,000 in 2008 [2]. The attributable fraction of cases due to HPV is approximately 88 percent [2,8]. HPV types 16 and 18 cause approximately 70 to 85 percent of anal cancers and precancerous anal lesions (ie, anal intraepithelial neoplasia grade 2 and grade 3 [AIN2/3]) [1,8,9]. Although it remains an uncommon cancer, the incidence of anal cancer is increasing in the United States and other countries [10-12]. In data from the Surveillance, Epidemiology and End Results program of the National Cancer Institute, the annual incidence among males and females between 1994 and 2000 was approximately 2 per 100,000 [10]. The annual incidence of anal cancer among men who have sex with men (MSM) was estimated to be as high as 37 per 100,000 prior to the HIV epidemic [13], and the incidence of anal cancer among HIV-positive MSM is estimated to be approximately twice that of HIV-negative MSM [14,15]. (See "Classification and epidemiology of anal cancer", section on 'Epidemiology and risk factors'.)
Genital warts — HPV types 6 and 11 also cause 90 percent of genital warts. The incidence of HPV infection was evaluated in 8800 females who were enrolled in the placebo arms of two randomized trials of the HPV quadrivalent vaccine [16]. Three percent of the placebo recipients developed genital warts over approximately four years, the vast majority of which were associated with HPV 6 or HPV 11 infection. (See "Epidemiology of human papillomavirus infections", section on 'Genital warts'.)
Genital warts are associated with physical and psychological morbidity and have a high rate of treatment failure; furthermore, treatment of recurrent episodes is costly [17]. (See "Condylomata acuminata (anogenital warts) in adults".)
Oropharyngeal cancer — HPV infection may also play a role in the pathogenesis of squamous cell carcinomas of the head and neck. HPV-associated oral cancers are primarily found in the oropharynx and base of the tongue and tonsil [18-20]. HPV has also been linked to cancer of the larynx [21]. In the United States, the incidence of HPV-associated oropharyngeal cancers has been rising and the incidence of non-HPV-associated cancers has been declining, such that the incidence of the former now exceeds that of the latter [12,22]. (See "Human papillomavirus associated head and neck cancer".)
HPV-related diseases in males
Penile cancer and precursor lesions — Penile cancer is rare globally, with an estimated incidence of 22,000 cancers in 2008; the attributable fraction due to HPV was 50 percent [2]. HPV 16 and HPV 18 cause approximately 35 to 40 percent of penile cancers and 70-80 percent of HPV-positive penile cancers [23].
AVAILABLE VACCINES — Three different vaccines, which vary in the number of HPV types they contain, are available in the United States:
Gardasil, a quadrivalent HPV vaccine, targets HPV types 6, 11, 16, and 18 [24].
Gardasil 9, a 9-valent vaccine, targets the same HPV types as the quadrivalent vaccine (6, 11, 16, and 18) as well as types 31, 33, 45, 52, and 58 [25].
Cervarix, a bivalent vaccine, targets HPV types 16 and 18 [26].
Dosing and administration is discussed elsewhere. (See 'Vaccine dose and administration' below.)
These are all prophylactic vaccines, designed to prevent HPV infection and subsequent HPV-associated lesions. Therapeutic vaccines, designed to induce regression of existing HPV-associated lesions, are in development but are not clinically available [27].
EFFICACY AND IMMUNOGENICITY IN FEMALES
Immunogenicity — Excellent antibody responses have been reported following immunization with both quadrivalent and bivalent vaccines [28-30]. Immunogenicity of the 9-valent vaccine among 9 to 26 year old females is comparable to that of the quadrivalent vaccine for the shared HPV types (6, 11, 16, and 18) [31,32].
Because efficacy studies were restricted to sexually active females, 15 years of age and older, immunological "bridging" studies have been conducted in females aged 9 to 15 years to demonstrate safety and immunogenicity. Following vaccination with the quadrivalent vaccine, the vaccine geometric mean titers (GMT) after 18 months in females aged 9 to 15 years were two- to threefold higher than in females aged 16 to 26 years for all targeted types [33]. Following vaccination with the 9-valent vaccine, the GMT in females aged 9 to 15 years were approximately twofold higher than in females aged 16 to 26 years for all targeted types [34,35]. Following vaccination with the bivalent vaccine, the GMT after seven months in females aged 10 to 14 years was noninferior to that observed in females aged 15 to 25 years, and in some studies, measured up to twofold higher [36-38].
In a head-to-head comparison of the immunogenicity of quadrivalent and bivalent HPV vaccines, immunization with the bivalent vaccine induced geometric mean titers of serum neutralizing antibodies 2.3- to 4.8-fold higher for HPV 16 and 6.8- to 9.1-fold higher for HPV 18 across all age strata compared with the quadrivalent vaccine [39]. Whether the induction of higher serum titers against HPV 16 and 18 has any impact on the degree and duration of protection is unknown. Furthermore, there is no defined minimum threshold titer for protection. Seroconversion from prior exposure has been shown to reduce the risk of incident HPV infection, suggesting that the titers resulting from natural infection, which are an order of magnitude lower than those elicited in vaccine studies, provide some level of protection [40,41].
Efficacy
Cervical, vaginal, and vulvar disease — Quadrivalent HPV vaccine [33,42], 9-valent HPV vaccine [31], and bivalent HPV vaccine [43] have been demonstrated in large clinical trials to prevent cervical disease, including cervical intraepithelial neoplasia (CIN2/3) and adenocarcinoma in situ. In these studies, HPV status was determined through serologic testing and DNA detection in cervical specimens, and vaccine effectiveness was greatest in females who did not have prior HPV infection. In addition, quadrivalent vaccine has also been demonstrated to reduce the incidence of genital warts and vaginal and vulvar intraepithelial neoplasia (VAIN and VIN 1-3).
Quadrivalent HPV vaccine — Two large, randomized, double-blind, placebo-controlled trials have evaluated the efficacy of quadrivalent HPV vaccine in more than 17,000 adolescents and young females [33,42].
Among HPV-naïve populations, the efficacy of quadrivalent HPV vaccine for preventing CIN2 or more severe disease due to HPV types included in the vaccine, was 97 to 100 percent.
In the overall population of study participants (with or without prior HPV infection), the efficacy of quadrivalent HPV vaccine for preventing CIN2, or more severe disease due to HPV types included in the vaccine was significantly lower at approximately 44 percent after a mean follow-up period of three years. This reduction in efficacy reflects the fact that the vast majority of enrollees in this trial were already sexually active and many had been previously infected with vaccine HPV types. (See 'Timing of immunization' below.)
Data collected outside the clinical trial setting are also favorable, demonstrating decreased prevalence of HPV-related cervical disease and genital warts following introduction of quadrivalent vaccine into national immunization programs. (See "Epidemiology of human papillomavirus infections", section on 'Effect of HPV vaccine'.)
9-valent vaccine — An international trial reported the efficacy of the 9-valent vaccine in approximately 14,000 females aged 16 to 26 years who were randomly assigned to receive the quadrivalent or 9-valent vaccine [31].
Among HPV-naïve populations, the efficacy of 9-valent vaccine for preventing CIN2 or more severe disease, VIN2 or 3, and VaIN2 or 3 associated with HPV types 31, 33, 45, 52, and 58 was 97 percent.
In the overall population of study participants (with and without prior HPV infection), the rates of high-grade cervical, vaginal, and vulvar disease were the same among women who received the 9-valent vaccine and those who received the quadrivalent vaccine (14 cases/1000 person years in both groups).
Bivalent HPV vaccine — One large randomized clinical trial in more than 18,000 young females aged 15 to 25 years demonstrated the efficacy of bivalent HPV vaccine [43].
Among HPV-naïve patients, the efficacy of the bivalent vaccine for preventing CIN2 or more severe disease due to HPV types included in the vaccine was 93 percent, comparable with the efficacy of the HPV quadrivalent vaccine.
In the overall population of study participants (with and without prior HPV infection), vaccine efficacy for preventing CIN2 or more severe disease due to HPV types included in the vaccine was significantly lower at 53 percent after a mean follow-up period of approximately three years. These data are consistent with those seen with HPV quadrivalent vaccine and emphasize the need to vaccinate individuals before the onset of sexual activity to gain the greatest benefit and maximize cost effectiveness. (See 'Timing of immunization' below.)
HPV vaccination appears to be safe and effective in preventing subsequent infection in older women, but the overall benefit is less than that in younger females [44]. In a trial of 5752 women older than 25 years who were randomly assigned to receive bivalent vaccine or placebo and followed for a mean of 40 months, vaccine efficacy for the combined endpoint (preventing six-month persistent cervical HPV type 16 or 18 infection or vaccine-type associated CIN grade 1 or more severe diagnoses) was 44 percent overall [45]. Among those who did not have a prior history of HPV infection and received all three doses of vaccine, vaccine efficacy was 81 percent. Rates of vaccine-type associated CIN2 or more severe diagnoses were not statistically different between HPV-naïve women who received vaccine or placebo.
Anal disease — There are no direct efficacy data regarding the prevention of anal intraepithelial neoplasia (AIN) and anal cancer in females specifically; however, since the majority of anal cancers in females are related to HPV 16 and HPV 18, a beneficial impact of vaccination to prevent anal intraepithelial neoplasia and anal cancer in females is anticipated. Additionally, in a study of women who had participated in a trial of the bivalent vaccine, vaccine efficacy against prevalently detected anal HPV types 16 and 18 infection was 84 percent, similar to the efficacy against cervical infection with these types [46]. Prevention of AIN and anal cancer is an indication for vaccination in females with the quadrivalent vaccine. (See 'Recommendations for HPV immunization in females' below.)
Oral disease — Bivalent HPV vaccination has also been associated with reduction in the prevalence of oral infection with HPV types 16 and 18. In a trial originally designed to evaluate the vaccine efficacy against cervical HPV disease among 7466 females in Costa Rica, fewer participants who were randomly assigned to receive bivalent HPV vaccination (1 of 2910) had detectable HPV types 16 or 18 on an oral specimen four years after vaccination compared with those who received the control hepatitis A vaccination (15 of 2924) [47]. Vaccine efficacy for the prevention of oral HPV was estimated to be 93 percent. Whether HPV vaccination can prevent the development of HPV-related oropharyngeal cancer has not yet been evaluated.
RECOMMENDATIONS FOR HPV IMMUNIZATION IN FEMALES
Indications and choice of vaccine — Various guideline committees have made recommendations regarding the use of HPV vaccine, which are discussed below. We are in general agreement with the recommendations from the United States Advisory Committee on Immunization Practices (ACIP). (See 'Advisory Committee on Immunization Practices' below.)
While all guidelines target the same age group for routine vaccination, they differ in the catch-up age range. This is primarily due to cost-effectiveness analyses which show the benefit and cost effectiveness is lower when vaccination is given at older ages. (See 'Cost effectiveness' below.)
Advisory Committee on Immunization Practices — The United States Advisory Committee on Immunization Practices (ACIP) recommends the bivalent, quadrivalent, or 9-valent HPV vaccine for females aged 11 to 12 for the prevention of cervical, vaginal, and vulvar cancer and the related precursor lesions caused by the HPV types targeted by these vaccines [48-50]. The ACIP also recommends the quadrivalent or 9-valent HPV vaccine for the prevention of anal cancer and its precursor lesions, and genital warts in females.
These vaccines can be administered to females as young as age nine. Catch-up vaccination is also recommended for females aged 13 to 26 years who have not been previously vaccinated or who have not completed their vaccine series.
We recommend the 9-valent vaccine given its greater HPV type coverage than the other HPV vaccines. Re-vaccination with the 9-valent vaccine is likely not warranted for individuals who have completed a series with a different HPV vaccine.
Pediatric, gynecologic, and family practice societies — Recommendations from the American Academy of Pediatrics (AAP), the American Academy of Family Practice (AAFP), and the American College of Obstetricians and Gynecologists (ACOG) are all largely consistent with the ACIP guidelines above.
American Cancer Society — Similar to the ACIP, the American Cancer Society (ACS) guidelines recommend that HPV vaccination should be routinely offered to females aged 11 to 12 years; immunization may begin at nine years of age [51]. However, the ACS recommends catch-up vaccination for females aged 13 to 18 who have not been previously vaccinated or completed their vaccine series. The ACS notes that there is insufficient evidence to recommend for or against vaccination of females aged 19 to 26 years.
World Health Organization — The World Health Organization (WHO) position paper suggests that girls within the age range of 9 through 13 years should be the primary target population for HPV immunization (www.who.int/wer). It notes that local public health programs should recommend vaccination of older females only if it is affordable and cost effective and does not divert resources from vaccinating the primary target population or screening for cervical cancer.
Timing of immunization — Clinical trial data of vaccine efficacy in males and females suggest that immunization with HPV vaccine is most effective among individuals who have not been infected with HPV (eg, patients who are "HPV-naïve"). Thus, the optimal time for HPV immunization is prior to an individual’s sexual debut. Neither vaccine treats or accelerates the clearance of pre-existing vaccine-type HPV infections or related disease.
Females who are sexually active should still be vaccinated consistent with age-specific recommendations. A history of an abnormal Papanicolaou test, genital warts, or HPV infection is NOT a contraindication to HPV immunization [49]. However, immunization is less beneficial for females who have already been infected with one of more of the HPV vaccine types.
EFFICACY AND IMMUNOGENICITY IN MALES — Interest in HPV vaccine efficacy and safety in young males has not only included prevention of HPV-related diseases (genital warts, anal cancer, and penile cancer), but also possible decreased transmission of HPV infection to female sex partners and potential for prevention of oral cancers associated with HPV 16 and 18 [20].
Immunogenicity — Studies with quadrivalent HPV vaccine, 9-valent HPV vaccine, and bivalent HPV vaccine have demonstrated that the proportions of vaccine recipients who achieve seroconversion is comparable in males (eg, 99 to 100 percent) and females (eg, 93 to 100 percent) [34,52,53]. Eighteen months following vaccination with the quadrivalent vaccine, the geometric mean titers (GMTs) against all four targeted types in males aged 9 to 15 years were noninferior to those in females of the same age [53]. Following vaccination with the 9-valent vaccine, the GMTs against all included HPV types in males aged 9 to 15 and aged 16 to 26 years were similar to those in females aged 16 to 26 years [34,35]. Following vaccination with bivalent vaccine, the GMTs against both targeted types in males aged 10 to 18 years and 10 to 14 years were higher than those historically reported for females aged 15 to 25 years and 10 to 14 years, respectively [52]. As in females, there is no defined minimum threshold titer for protection in males. (See 'Immunogenicity' above.)
Efficacy — In a placebo-controlled international trial, the efficacy of quadrivalent HPV vaccine was evaluated among 4065 males aged 16 to 26 [54]. The following results were demonstrated:
The efficacy of immunization against the development of external genital lesions and persistence of HPV infection (by HPV 6, 11, 16, or 18 types) was 90 percent and 86 percent, respectively, among HPV-naïve males (no evidence of infection with the relevant HPV vaccine types at enrollment) who received all three doses of vaccine.
In contrast, vaccine efficacy was significantly lower among the overall patient population with or without HPV infection at enrollment (66 percent for the prevention of external genital warts and 48 percent for the prevention of persistent HPV infection).
The efficacy of HPV immunization in preventing anal intraepithelial neoplasia secondary to the relevant HPV vaccine types was assessed in a planned sub-study of 602 men who have sex with men (MSM). Similar to the above results, vaccine efficacy was higher in the HPV-naïve compared with the overall MSM population (78 versus 50 percent, respectively).
RECOMMENDATIONS FOR HPV IMMUNIZATION IN MALES
Indications and choice of vaccine — The Advisory Committee on Immunization Practices (ACIP) recommends the routine use of quadrivalent or 9-valent HPV vaccine in males aged 11 or 12 years [48-50]. The vaccination series can be administered to individuals as young as nine years. Vaccination is also recommended for males aged 13 to 21 years who have not been vaccinated previously or who have not completed the three-dose series. For males who have sex with males (MSM) and for males who are immunocompromised (including HIV infection), ACIP recommends vaccination through age 26 for those not previously vaccinated.
For other males, the ACIP supports "permissive use" of HPV vaccination in males aged 22 through 26 years. Permissive use means that the vaccine is recommended, but not considered to be of sufficient priority to include on routine vaccination schedules. Vaccines recommended on a permissive basis are less likely to be covered by a patient’s health insurance company.
We recommend the 9-valent vaccine over the quadrivalent vaccine for males given its greater HPV type coverage. Although it is not clear that greater HPV type coverage would substantially improve male cancer prevention, it would likely further reduce the risk of cervical cancer in women indirectly through herd immunity. Repeat vaccination with the 9-valent vaccine is likely not warranted for individuals who have completed a series with a different HPV vaccine.
The decision of the ACIP panel to recommend HPV vaccination among males was based on: a) vaccine efficacy data on genital warts and persistent HPV infection and prevention of anal intraepithelial neoplasia in MSM [54,55] and b) vaccine safety data [56]. Cost-effectiveness analyses have suggested that male vaccination is less cost effective than female vaccination [57,58]. However, the overall cost effectiveness of male vaccination depends on a range of assumptions, such as vaccine efficacy, vaccine coverage of females, the range of health outcomes included, and the effect of HPV-associated diseases on quality of life [49]. Male vaccination may be more cost effective with low vaccination coverage among females, which is the current situation in the United States [59].
Timing of immunization — Clinical trial data of vaccine efficacy in males and females suggest that immunization with HPV vaccine is most effective among individuals who have not been infected with HPV (eg, patients who are "HPV-naïve"). Thus, the optimal time for HPV immunization is prior to an individual’s sexual debut. Neither vaccine treats or accelerates the clearance of pre-existing vaccine-type HPV infections or related disease.
Males who are sexually active may still be vaccinated consistent with age-specific recommendations. A history of anal intraepithelial neoplasia, genital warts, or HPV infection is NOT a contraindication to HPV immunization [49]. However, immunization is less beneficial for males who have already been infected with one or more of the HPV vaccine types.
Controversies — Opponents of HPV immunization in males argue that [60]:
The burden of HPV-associated diseases such as anal, penile, and oropharyngeal cancers in males is less than that of cervical cancer in females [61].
Public health initiatives should be most focused on attaining high rates of immunization in young girls as it is the most cost effective.
Proponents of HPV immunization in males argue that:
Immunization rates in young girls have been generally low, particularly when immunizations are not mandatory [62]. It is under these conditions that both incremental benefit and cost effectiveness of vaccinating males have been shown [63].
High coverage programs in females confer protection against HPV-related infection and disease in heterosexual males, but not MSM.
HPV infection is common in males and is readily transmitted, influencing disease infection rates in both males and females [64,65].
One modeling study highlighted the incomplete protection of men from HPV-associated disease if only females are vaccinated [63]. Using population data from the Netherlands, it estimated that the burden of HPV-associated cancers in men would be reduced by 37 and 66 percent if vaccine uptake among girls and young women were 60 and 90 percent, respectively. Vaccine uptake among females is considerably less than 60 percent in many locations. (See 'Strategies to improve vaccine coverage' below.)
IMMUNIZATION IN SPECIAL PATIENT POPULATIONS
Pregnant females — Although none of the approved HPV vaccines contain live virus, use in pregnancy is not recommended because of limited data on safety [49]. Lactating females can receive the immunization series since subunit vaccines do not affect the safety of infant breastfeeding. (See "Immunizations during pregnancy".)
If a woman receives the HPV vaccine before she knows that she is pregnant she should be reassured that there is no evidence that this vaccine will harm the pregnancy. This is discussed in detail elsewhere. (See "Immunizations during pregnancy", section on 'Human papillomavirus'.)
Females who have started the series, but become pregnant before completion of all three shots, may resume the series when postpartum. (See "Immunizations during pregnancy".)
Both vaccine manufacturers maintain pregnancy registries to monitor fetal outcomes of pregnant females exposed to HPV vaccine [49]. In the United States, exposures to the quadrivalent vaccine can be reported by calling 877-888-4231, and exposures to the bivalent vaccine can be reported by calling 888-452-9622.
Immunization in females with pre-existing cervical abnormalities or genital warts — A history of genital warts, abnormal cytology, or positive HPV DNA test result is not evidence of prior infection with any or all of the vaccine HPV types, and vaccination can still provide protection against infection with HPV vaccine types not already acquired. Thus, the Advisory Committee on Immunization Practices (ACIP) recommends immunization for females (up to 26 years of age) with any such history [48,49]. Additionally, the ACIP recommends against assessment with Pap testing or screening for existing HPV infection as part of the determination for HPV vaccine candidacy.
However, these patients should be advised that vaccination will have no therapeutic effect on pre-existing HPV infection or cervical intraepithelial neoplasia, and the potential benefit of HPV vaccination is not as great as if they were vaccinated before they started having sex.
Immunosuppressed or immunocompromised hosts — Transplant recipients and HIV-infected patients, particularly those with low CD4 counts (<200 cells/mm3) are at risk for HPV-related disease. (See "HIV and women", section on 'Abnormal cervical cytology'.)
Studies of the HPV quadrivalent vaccine in HIV-infected adult men [66], HIV-infected women aged 16 to 23 years [67,68], and HIV-infected boys and girls aged 7 to 12 years [69] suggest that it is both immunogenic and safe in these populations. However, efficacy data are not yet available. Studies in other immunocompromised populations are ongoing.
HPV vaccine is recommended by the ACIP for persons who are immunocompromised as a result of infection, disease, or medications through age 26 years if they have not already received any or all vaccine doses [48,49]. It is not a live vaccine. HPV vaccination in transplant recipients is discussed elsewhere. (See "Immunizations in solid organ transplant candidates and recipients", section on 'Human papillomavirus' and "Immunizations in hematopoietic cell transplant candidates and recipients", section on 'Human papillomavirus'.)
Cervical cancer screening continues to play an important role in detection and treatment of cervical intraepithelial neoplasia (CIN) 2, 3, and cervical cancer in these high-risk females. Although there are no formal guidelines regarding screening for precancerous anal lesions, some specialists recommend anal cytologic screening for HIV-1-infected males and females. (See "Cervical intraepithelial neoplasia: Terminology, incidence, pathogenesis, and prevention" and "HIV and women" and "Immunizations in HIV-infected patients" and "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment", section on 'Screening for anal SIL'.)
Healthcare workers — The Advisory Committee on Immunization Practices (ACIP) immunization schedule of 2012 indicates that healthcare personnel are not at increased risk of HPV infection due to occupational exposure; age-based recommendations noted above still apply [70].
PREVACCINATION ASSESSMENT — The ACIP does not recommend serologic or HPV DNA testing prior to immunization in females or males [49].
VACCINE DOSE AND ADMINISTRATION
Immunization schedule — In the United States, the HPV vaccine series is three vaccine doses given over a minimum of 24 weeks [49]. The minimum interval between the first two doses is four weeks and the minimum interval between the second and third doses is 12 weeks. The quadrivalent vaccine (Gardasil) and 9-valent vaccine (Gardasil 9) are typically administered in three doses at time zero, and at two and six months of follow-up. The bivalent vaccine (Cervarix) is typically administered in three doses at time zero, and at one and six months of follow-up. HPV vaccine can be safely administered at the same time as other age-appropriate vaccines at a different anatomic site.
In general, the same formulation should be used to complete the series, if possible. However, if the HPV vaccine formulation initially used is unknown or unavailable, or if the 9-valent vaccine is being introduced into the formulary, a different HPV vaccine formulation can be used to complete the series [50].
In some countries, two doses of HPV vaccine are recommended because of evidence of generally comparable immunogenicity and, for some outcomes, efficacy after two versus three doses. This evidence is discussed in detail elsewhere (see 'Missed doses/alternative schedules' below). As an example, the Strategic Advisory Group of Experts on Immunizations (SAGE) of the World Health Organization recommends two doses for females under the age of 15 and three doses for those who initiate vaccination later [71]. Practitioners outside the United States should consult local guidelines for the recommended immunization schedule in their country.
Administering HPV vaccine at the same time as certain other vaccines (ie, tetanus, acellular pertussis, and diphtheria vaccine and inactivated poliovirus vaccine) does not appear to adversely affect the immune response to either the HPV vaccine or the concomitant vaccine [72,73].
Missed doses/alternative schedules — Patients often do not follow up for their immunizations on schedule [74]. The Advisory Committee on Immunization Practices (ACIP) recommends that if the vaccination series is interrupted for any length of time, it can be resumed without restarting the series.
Because of the frequency of missed doses and the suboptimal adherence to a three dose vaccine schedule, there has been interest in whether fewer doses or greater time intervals between doses remain effective. Randomized trials are planned to evaluate this issue. Some observational data suggest that administration of two vaccine doses has comparable efficacy against vaccine type HPV infection and, for the quadrivalent vaccine, the incidence of genital warts, and is comparably immunogenic as three doses, but there have been no studies evaluating the efficacy of fewer than three doses on prevention of cervical neoplastic disease. In some countries (not the United States), the recommended vaccine series for certain individuals consists of two doses. A single vaccine dose is not a recommended option. (See 'Immunization schedule' above.) In an analysis of data from two trials of the bivalent HPV vaccine in young women (aged 15 to 25 years) who had no HPV type 16 or 18 infection at baseline and who had at least 12 months of follow-up, vaccine efficacy against six-month persistent infection with those HPV types was no different in women who received the intended three doses compared with those who received fewer doses (89, 90, and 97 percent efficacy with three, two, and one vaccine doses, respectively) [75]. For women who received only two doses, vaccine efficacy was generally similar among those who received the second dose one or six months after the first. However, cross-protective efficacy against non-vaccine types with two doses given one month apart was inferior to both three doses and two doses given six months apart.
Similarly, one observational study suggested that two quadrivalent vaccine doses provided substantial protection against genital warts, although completion of three doses was slightly superior [76]. In the study, over one million Swedish females aged 10 to 24 years who did not have a history of genital warts or HPV vaccination at study entry were followed for a mean of 3.8 years. Receipt of three doses of vaccines was associated with the lowest subsequent incidence of genital warts (128 versus 528 events per 100,000 person years without vaccination), but receipt of two doses and one dose were also associated with a substantially lower incidence (174 events and 384 per 100,000 person years, respectively). Among females who were aged 10 to 16 years when first vaccinated, after adjusting for parental education and age, three doses of the vaccine were associated with 59 fewer events per 100,000 person-years (95% CI 2-117) than two doses and 75 fewer events per 100,000 person years (95% CI -7-157) than one dose. In a similar study from Denmark, three quadrivalent vaccine doses were also associated with an overall lower risk of genital warts than two doses, but when the two vaccine doses were administered at least six months apart, the reduction in risk for genital warts appeared comparable to that with three doses [77].
Other studies have examined the effects of varied dosing schedules on immunogenicity, as an indirect measure of potential efficacy. In an analysis of a Costa Rican trial of bivalent HPV vaccination, seropositivity against HPV types 16 and 18 four years after vaccination was 100 percent among those who had only received one dose (n = 78), two doses separated by one month (n = 140), or two doses separated by six months (n = 52) [78]. Antibody levels were comparable between those who received two doses separated by six months and a random selection of women who received all three doses as intended. A clinical trial in Vietnam, which evaluated three alternative schedules with longer intervals between vaccine doses compared with standard dosing among 809 girls (aged 11 to 13 years), found equivalent HPV antibody titers one month after the final dose [79]. A follow-up analysis suggested that antibody titers were comparable across dosing schedules after two and a half years [80]. A randomized trial to evaluate the immune response to two doses (at zero and six months) versus standard three doses (at zero, two and six months) found that the antibody responses following two doses was noninferior to three doses for all four HPV types at seven months but inferior for HPV18 and HPV6 at 36 months [81].
Postvaccination serology — There is no evidence that the measurement of postvaccination antibody titers to monitor immunity is useful for determining who is protected against infection by the vaccine-targeted types.
Duration of protection — HPV vaccines have shown excellent duration of protection for the time periods through which they have been studied. Continued protection against high grade cervical, vaginal, and vulvar neoplasia has been observed through 42 months following vaccination among female trial participants [82]. Persistent antibody levels and protection against HPV infection have been reported up to 10 years following vaccination [83-85]. Of note, the precise level of antibody needed for protection against infection is unknown. Further data will become available in the future as female and male participants in vaccine studies are followed over time.
VACCINE SAFETY — All vaccines use virus-like particles (VLPs), which mimic the viral capsid. VLPs do not contain genetic material and are produced in biologic systems, which have well-established safety records [86].
All vaccines appear to be safe in the context of clinical trials, although more is known about the safety profile of the quadrivalent vaccine than the 9-valent or bivalent vaccines due to availability of more postlicensure data, which are summarized below [87].
Quadrivalent vaccine (Gardasil) — Vaccine safety data are now available from both registration trials and in postlicensure safety surveillance systems. Different types of information can be gleaned from these two processes. The advantage of safety reviews within the context of a clinical trial is that medical chart reviews of adverse events are usually more thorough and complete, whereas surveillance systems are voluntary and passive. However, postlicensure surveillance systems have the advantage of identifying a potentially serious side effect that may have been too rare to detect during prelicensure trials.
The postlicensure safety profile is broadly consistent with safety data from prelicensure trials that suggest the vaccine is safe and well tolerated apart from mild injection site reactions, although syncopal events have emerged as a potential serious adverse effect [88]. The incidence of syncope among adolescents has increased overall with the introduction of other routine immunizations as well, such as meningococcal vaccine [88,89]. The ACIP recommends a routine 15-minute waiting period following vaccination so that the patient may continue in a sitting or supine position as needed; this may decrease the risk of syncope with subsequent injury.
In light of the growing data on the safety of the HPV vaccine, the World Health Organization’s Global Advisory Committee on Vaccine Safety stated that the benefit-risk profile remains favorable [90]. Additionally, it notes concern about claims of harm raised on the basis of anecdotal reports in the absence of biological or epidemiological substantiation.
Prelicensure trial data — The safety profile of the quadrivalent vaccine was evaluated in diverse populations of females from resource-rich and resource-limited settings [33,42]. Mild injection site reactions were the most commonly observed adverse events [91,92]. The safety profile of quadrivalent vaccine in males was reported to be similar to that of studies in females [54].
Postlicensure data — In the United States, adverse events following immunization are collected and analyzed within the Vaccine Adverse Event Reporting System (VAERS) [88,93,94]. Adverse events following HPV vaccine are compared with background rates following other immunizations. Between June 2006 and March 2013, approximately 57 million doses of quadrivalent HPV vaccines were distributed in the United States. Reports of adverse events to VAERS have been consistent with the pre-licensure data:
From 2006 to 2013, VAERS received 21,194 reports of adverse events following HPV immunization among females [94]. The vast majority (92 percent) were considered mild. The proportion of events reported as serious peaked in 2008. Among serious events, headache, nausea, vomiting, fatigue, dizziness, syncope, and generalized weakness were the most frequently reported. There is no increased risk of Guillain-Barré Syndrome compared with other vaccines in similar age groups [88].
Through 2011, 72 post-vaccination deaths had been reported, of which 34 were confirmed. There was no unusual pattern or clustering to the deaths that would suggest that they were caused by the vaccine [93].
Other studies have similarly observed that the quadrivalent vaccine is generally safe [56,95,96].
There does appear to be an increased risk of syncope with the quadrivalent vaccine, but whether this is unique to this vaccine is unclear. A disproportionate number of syncopal events following quadrivalent vaccine administration had been reported to the VAERS [88]. Among the 1896 syncopal events reported, 15 percent resulted in a fall or injury. Similarly, in an industry-sponsored study of almost 190,000 females in a large healthcare system who received at least one vaccine dose, emergency department visits or hospitalizations were higher during the post-vaccine period compared with a subsequent control period for 10 of 265 diagnostic categories evaluated, including viral, bacterial, and skin infections and congenital anomalies [95]. An independent safety committee concluded that same-day syncopal events (OR 6.0, 95% CI 3.9-9.2) and local skin infections within two weeks of vaccination (OR 1.8, 95% CI 1.3-2.4) were the only adverse events likely associated with vaccine administration.
Other adverse events that appeared to be vaccine-related have not been substantiated by further study. Although venous thromboembolism (VTE) rates reported to the VAERS were higher for quadrivalent vaccine than other vaccines, of the 31 patients with thromboembolism reported through 2008, 28 (90 percent) had a known risk factor (ie, estrogen-containing birth control pills or a family history of clotting disorder) [88]. In a study of adverse events following over 600,000 quadrivalent vaccine doses administered to females in seven large managed care organizations, there was a nonsignificant increase in the risk of VTE following vaccination among females aged 9 to 17 years, but individual review of the eight potential VTE cases indicated that only five met the standard case definition and all had other known risk factors for VTE (eg, oral contraceptive use, coagulation disorders, smoking, obesity, or prolonged hospitalization) [56]. Additionally, in a study of 1.6 million Danish women, of whom 30 percent had received quadrivalent HPV vaccine, there were over 4000 cases of incident VTE, but there was no association between vaccine receipt and VTE [97].
Anaphylaxis had also been reported following administration of the quadrivalent vaccine [88,98], although this risk has not been confirmed in other studies. In a mass school-based national vaccination program in Australia, the incidence of anaphylaxis was 2.6 per 100,000 doses [98]. However, some of those cases were subsequently thought not to have represented anaphylaxis and other studies from Australia did not confirm this high rate [99,100]. In the VAERS surveillance system, only 10 cases met predefined criteria for anaphylaxis; the overall risk ratio was 0.1 case per 100,000 doses distributed [88]. (See "Allergic reactions to vaccines".)
Although anecdotal and sporadic case reports had raised concerns about a potential causal relationship between HPV vaccination and development of multiple sclerosis and other demyelinating disorders, larger studies have refuted this. In a study of nearly four million Swedish and Danish females aged 10 to 44 years, receipt of quadrivalent vaccination was not associated with demyelinating diseases, including multiple sclerosis, optic neuritis, transverse myelitis, and acute disseminated encephalomyelitis, as documented by billing codes [101].
9-valent vaccine (Gardasil 9) — In a trial in which over 7000 females received the 9-valent vaccine, the main reported adverse effects were mild or moderate injection site reactions (pain, erythema, and swelling). These occurred slightly more frequently than with the quadrivalent vaccine [34]. The frequency of systemic adverse effects (eg, headache, fever, nausea, dizziness) was similar with the 9-valent and quadrivalent vaccines.
Bivalent vaccine (Cervarix) — In a phase III, multinational prospective, double-blind, placebo-controlled trial of more than 18,000 females aged 15 to 25 years, the vaccine was well tolerated and there were no differences in serious adverse events between vaccine and placebo recipients. Because of low uptake of Cervarix in the US as of September 2011, only sparse postlicensure data are available. As of September 2011, there have been 52 VAERS reports of adverse events following administration of bivalent vaccine and the majority of these adverse events (98 percent) were considered nonserious.
Behavioral impact — Some surveys of parents found a concern for sexual disinhibition in adolescent girls following HPV vaccine receipt, particularly among older and ethnic minority parents [102,103]. Studies have not supported an increase in risky sexual behavior following vaccination [104-106]. In a retrospective study of preteenage girls enrolled in a large healthcare system, the combined incidence of pregnancy testing, chlamydia testing, and contraception counseling was determined among those girls who did (n = 493) and did not (n = 905) receive at least one HPV vaccine dose [104]. After adjustment for baseline healthcare utilization, race, and socioeconomic status, HPV vaccination was not associated with an increased rate of these sexual activity-related outcomes.
WHERE TO REPORT ADVERSE EVENTS — Additional data on the Vaccine Adverse Event Reporting System are available on the web [93]. Instructions for reporting adverse events to the Vaccine Adverse Event Reporting System are available at www.vaers.hhs.gov or by calling 800-822-7967 in the United States.
STRATEGIES TO IMPROVE VACCINE COVERAGE — Some countries, such as Australia, the United Kingdom, and Denmark, have achieved relatively high full-dose uptake of HPV vaccination (> 60 percent) through inclusion of the vaccine in national vaccination programs [107-109]. In the United States, uptake of HPV vaccination has been suboptimal. In 2012, based on results of a national survey among adolescents who had provider-reported vaccination records, estimated vaccine coverage among females aged 13 to 17 was 54 percent for at least one dose and only 33 percent for three doses [94]. In the survey, parents who did not intend to have their daughters vaccinated gave the following as their top five reasons: the vaccine was not needed, the vaccine was not recommended, concern about vaccine safety, lack of knowledge about the vaccine or disease, and lack of sexual activity by their daughter. This highlights a lack of understanding about the rationale for HPV vaccination on the part of the parent and the important role of the healthcare provider in consistently and clearly educating parents about vaccination.
Lack of opportunity did not appear to be a major reason for low vaccine coverage. Of the unvaccinated females in the survey, 84 percent had at least one medical visit at which they were given a different vaccine but not the HPV vaccine [94]. Vaccination rates may be particularly low among certain demographic subgroups. As an example, in a survey of 3253 females aged 15 to 25 years, only 29 percent reported initiating HPV vaccination despite 84 percent being aware of it [110]. Among self-described lesbians, only 9 percent of those aware of HPV vaccination had received it.
The implications of these findings are significant. Some experts estimate that by increasing three-dose HPV vaccination coverage to 80 percent in females, approximately 53,000 additional cases of cervical cancer could be prevented in the US over the lifetimes of those currently aged ≤12 years [58,94].
Attempted community- or practice-based interventions to improve uptake of HPV vaccine include patient reminders, physician-focused interventions (auditing and feedback or alerts to remind physicians to offer vaccination), school-based vaccination programs, and social marketing strategies. In a systematic review of studies evaluating the efficacy of such interventions, most suggested an improvement in at least one HPV vaccination outcome (eg, initiation or completion of greater number of doses) with these strategies [111].
IMPORTANCE OF CANCER SCREENING
Cervical screening — Cervical cancer screening with cervical cytology (ie, Papanicolaou test) has reduced the incidence and mortality of cervical cancer by more than 70 percent over the past six decades [112]. Screening for cervical cancer by cervical cytology and/or HPV testing is recommended for all females beginning at age 21 [113]. A preventive healthcare visit is an opportune time to discuss and offer HPV vaccination and/or cervical screening depending on the age of the woman [51]. Detailed information regarding screening for cervical cancer is found elsewhere. (See "Screening for cervical cancer".)
Cervical cancer screening continues to be of great importance since immunization with the bivalent or quadrivalent HPV vaccine will not prevent approximately 25 to 30 percent of cervical cancers in HPV-naïve females and does not protect females already infected with carcinogenic HPV types against the development of cancer. The optimal approach to cervical cancer screening in HPV-naïve females who have received the 9-valent vaccine and are thus protected against 90 percent of cervical cancer is unclear, but until further data are available, screening should continue for all vaccinated females.
Anal screening — Although there are no formal guidelines regarding screening for precancerous anal lesions, some specialists recommend anal cytologic screening for HIV-1-infected males and females. (See "Cervical intraepithelial neoplasia: Terminology, incidence, pathogenesis, and prevention" and "HIV and women" and "Immunizations in HIV-infected patients" and "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment", section on 'Screening for anal SIL'.)
COST EFFECTIVENESS — Mathematical models have examined the cost effectiveness of HPV vaccination [114-117]. One study suggested that vaccination of the entire United States population of 12-year-old girls would annually prevent more than 200,000 HPV infections, 100,000 abnormal cervical cytology examinations, and 3300 cases of cervical cancer if cervical cancer screening continued as currently recommended [114].
Vaccination becomes increasingly less cost effective with increasing age. Assuming that HPV vaccine provides lifelong immunity, the cost-effectiveness ratio is $43,600 per quality-adjusted life-year (QALY) gained when vaccinating 12-year-old girls [118]. However, in one analysis the cost of extending immunizations up to the age of 26 years was $152,700 per QALY [118]. As in all cost-effectiveness studies, interpretation of these findings is limited by uncertainty and multiple assumptions made in the models.
In various models, vaccinating both males and females is predicted to be more beneficial in reducing HPV infection and disease than by vaccinating only females, but at a higher cost than vaccinating females alone [118-120]. However, models of cost effectiveness are limited by uncertainty regarding major issues such as duration of protection [121], the effect of herd immunity, level of vaccine uptake among girls and females, and the prevalence of vaccine-specific HPV types circulating in age-specific populations [122]. (See "Epidemiology of human papillomavirus infections".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
SUMMARY AND RECOMMENDATIONS
Persistent viral infection with carcinogenic HPV types causes virtually all cancer of the cervix and most cases of anal cancer. The carcinogenic types, HPV 16 and HPV 18, which are targeted by the current HPV vaccines, cause approximately 70 percent of all cervical cancers worldwide and 72 percent of anal cancers. HPV types 31, 33, 45, 52, and 58 are estimated to cause an additional 19 percent of invasive cervical cancers. HPV 6 and HPV 11 cause approximately 90 percent of genital warts. (See 'Disease associations' above.)
The quadrivalent vaccine (Gardasil) includes HPV types 6, 11, 16, and 18. The 9-valent vaccine (Gardasil 9) includes HPV types 6, 11, 16, 18, 31, 33, 45, 52, and 58. The bivalent vaccine (Cervarix) includes HPV types 16 and 18. (See 'Available vaccines' above.)
HPV immunization is most effective among individuals who have not yet been infected with HPV (eg, before sexual debut). (See 'Timing of immunization' above.)
Multicenter, double-blind, placebo-controlled trials have demonstrated efficacy of quadrivalent, 9-valent, and bivalent HPV vaccines against incident and persistent cervical HPV infection due to vaccine types and the development of cervical intraepithelial neoplasia. Quadrivalent and 9-valent vaccines also have demonstrated high efficacy against vaccine type-associated vaginal and vulvar intraepithelial neoplasia. They also protect against genital warts associated with HPV 6 and HPV 11. The efficacy of any HPV vaccine for the prevention of anal intraepithelial neoplasia has not been studied in females. (See 'Efficacy and immunogenicity in females' above.)
We recommend HPV immunization of females, as advised by multiple expert panels (Grade 1A). If cost and availability are not issues, we recommend the 9-valent vaccine for females in whom HPV vaccination is indicated (Grade 1B). Routine immunization should be offered to girls 11 to 12 years of age, but can be administered as early as nine years. Catch-up vaccination should be offered for females aged 13 to 26 years who have not been previously vaccinated. (See 'Recommendations for HPV immunization in females' above.)
Quadrivalent HPV vaccine is effective in preventing genital warts in young males and anal intraepithelial neoplasia among men who have sex with men (MSM). Immunogenicity of the 9-valent vaccine in males is similar to that in females. (See 'Efficacy and immunogenicity in males' above.)
We recommend HPV vaccination in males, as advised by expert panels (Grade 1B). If cost and availability are not issues, we recommend the 9-valent vaccine for males in whom HPV vaccination is indicated (Grade 1B). Routine immunization should be offered to boys aged 11 to 12, but can be administered as early as nine years of age. Catch-up vaccination should be offered for males between the ages of 13 to 21 who have not been previously vaccinated. For MSM, catch-up vaccination should be offered up to age 26. (See 'Indications and choice of vaccine' above.)
Although neither HPV vaccine contains live virus, use in pregnancy is not recommended because of limited data on safety. (See 'Pregnant females' above.)
Serologic testing or HPV DNA testing is not required prior to immunization. (See 'Prevaccination assessment' above.)
We suggest immunization of immunocompromised or immunosuppressed individuals with the HPV vaccine, including those with HIV infection, following the same guidelines as for immunocompetent patients (Grade 2C). Catch-up vaccination among these patients is recommended up to age 26 years. Cytologic screening continues to play an important role in detection and treatment of cervical intraepithelial neoplasia grades 2 and 3 and adenocarcinoma in situ and prevention of cervical cancer in these high-risk patients. (See 'Immunization in special patient populations' above and "Screening for cervical cancer" and "Anal squamous intraepithelial lesions: Diagnosis, screening, prevention, and treatment".)
The quadrivalent vaccine and 9-valent are administered in three doses at time zero, and at two and six months of follow-up. The bivalent vaccine is administered in three doses at time zero, and at one and six months of follow-up. (See 'Vaccine dose and administration' above.)
In prelicensure clinical trials and postlicensure monitoring, vaccines have been demonstrated to be generally safe. (See 'Vaccine safety' above.)
Cervical cancer screening is recommended for any woman 21 years of age or older. Clinicians should be aware that HPV immunization is not effective in clearing cytologically evident disease or HPV infection that is already present. (See 'Importance of cancer screening' above and "Screening for cervical cancer".)
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