hpv vaccine hpv vaccine human papillomavirus (hpv) vaccines are vaccines that prevent infection by certain types of human papillomavirus (hpv). available hpv vaccines protect against either two, four, or nine types of hpv. all hpv vaccines protect against at least hpv types 16 and 18, which cause the greatest risk of cervical cancer. it is estimated that hpv vaccines may prevent 70% of cervical cancer, 80% of anal cancer, 60% of vaginal cancer, 40% of vulvar cancer, and show more than 90% efficacy in preventing hpv-positive oropharyngeal cancers. they additionally prevent some genital warts, with the quadrivalent and nonavalent vaccines that protect against hpv types hpv-6 and hpv-11 providing greater protection. hpv vaccinevaccine descriptiontargethuman papillomavirus (hpv)vaccine typeprotein subunitclinical datatrade namesgardasil, cervarix, othersahfs/drugs.commonographmedlineplusa615028license data us dailymed: human_papillomavirus_vaccine pregnancycategory au: b2 routes ofadministrationintramuscular injectionatc codej07bm01 (who) j07bm02 (who) j07bm03 (who)legal statuslegal status au: s4 (prescription only) ca: rx-only, schedule d uk: pom (prescription only) us: ℞-only eu: rx-only identifierscas number910046-32-1chemspidernone ny (what is this?) (verify) the world health organization (who) recommends hpv vaccines as part of routine vaccinations in all countries, along with other prevention measures. the vaccines require two or three doses depending on a person's age and immune status. vaccinating girls around the ages of nine to thirteen is typically recommended. the vaccines provide protection for at least 5 to 10 years. cervical cancer screening is still required following vaccination. vaccinating a large portion of the population may also benefit the unvaccinated. hpv vaccines are very safe. pain at the site of injection occurs in about 80% of people. redness and swelling at the site and fever may also occur. no link to guillain–barré syndrome has been found. the first hpv vaccine became available in 2006. as of 2022, 125 countries include hpv vaccine in their routine vaccinations for girls, and 47 countries also for boys. it is on the world health organization's list of essential medicines and prequalified vaccines. vaccination may be cost effective in the low and middle-income countries. as of 2017, gardasil 9 is the only hpv vaccine available in the united states, as it provides protection against more hpv types than the earlier approved vaccines (the original gardasil and cervarix). medical uses gardasil syringe hpv vaccines are used to prevent hpv infection and therefore cervical cancer. vaccinating females between the ages of nine to thirteen is typically recommended, with many countries also vaccinating males in that age range. in the united states, the cdc recommends that all 11- to 12-year-olds receive two doses of hpv vaccine, administered 6 to 12 months apart. the vaccines require three doses for those ages 15 and above. hpv vaccines are recommended in the united states for women and men who are 9–26 years of age, and are also approved for those who are 27–45 years of age. hpv vaccination of large percentage of people within a population has been shown to decrease rates of hpv infections, with part of the benefit from herd immunity. since the vaccines only cover some high-risk types of hpv, cervical cancer screening is recommended even after vaccination. in the u.s., the recommendation is for women to receive routine pap smears beginning at age 21. in australia, the national screening program has changed from the two yearly cytology (pap smears) to being based on tests for hpv dna, based on work by karen canfell and others. efficacy the hpv vaccine has been shown to prevent cervical dysplasia from the high-risk hpv types 16 and 18 and provide some protection against a few closely related high-risk hpv types. however, there are other high-risk hpv types that are not affected by the vaccine. the protection against hpv 16 and 18 has lasted at least eight years after vaccination for gardasil and more than nine years for cervarix. it is thought that booster vaccines will not be necessary. gardasil and gardasil 9 protect against hpv types 6 and 11 which can cause genital warts. cervarix is just as effective at protecting women against persistent hpv 16 and 18 infection in the anus as it is at protecting them from these infections in the cervix. overall, about 30 percent of cervical cancers will not be prevented by these vaccines. also, in the case of gardasil, ten percent of genital warts will not be prevented by the vaccine. neither vaccine prevents other sexually transmitted diseases, nor do they treat existing hpv infection or cervical cancer. hpv types 16, 18 and 45 contribute to 94% of cervical adenocarcinoma (cancers originating in the glandular cells of the cervix). while most cervical cancer arises in the squamous cells, adenocarcinomas make up a sizable minority of cancers. further, pap smears are not as effective at detecting adenocarcinomas, so where pap screening programs are in place, a larger proportion of the remaining cancers are adenocarcinomas. trials suggest that hpv vaccines may also reduce the incidence of adenocarcinoma. two doses of the vaccine may work as well as three doses. the centers for disease control and prevention (cdc) recommends two doses in those less than 15 years and three doses in those over 15 years. a single dose might be effective. a study with 9vhpv, a 9-valent hpv vaccine that protects against hpv types 6, 11, 16, 18, 31, 33, 45, 52, and 58, came to the result that the rate of high-grade cervical, vulvar, or vaginal disease was the same as when using a quadrivalent hpv vaccine. a lack of a difference may have been caused by the study design of including women 16 to 26 years of age, who may largely already have been infected with the five additional hpv types that are additionally covered by the 9-valent vaccine. males hpv vaccines are approved for males in several countries and regions, including switzerland, portugal, canada, australia, ireland, south korea, hong kong, the united kingdom, new zealand, the netherlands, and the united states. in males, gardasil may reduce their risk of genital warts and precancerous lesions caused by hpv. this reduction in precancerous lesions might be predicted to reduce the rates of penile and anal cancer in men. gardasil has been shown to also be effective in preventing genital warts in males. while gardasil and the gardasil 9 vaccines have been approved for males, a third hpv vaccine, cervarix, has not. unlike the gardasil-based vaccines, cervarix does not protect against genital warts. since penile and anal cancers are much less common than cervical cancer, hpv vaccination of young men is likely to be much less cost-effective than for young women. gardasil is also used among men who have sex with men, who are at higher risk for genital warts, penile cancer, and anal cancer. recommendations by national bodies australia introduced hpv vaccination for boys over 12 from 2013 onwards, while uk and ireland introduced hpv vaccination for boys aged 12 and 13 as part of their national immunization plan in 2019. portugal introduced universal hpv vaccination for boys aged 10 years and above as part of its national immunization plan in 2020. on 9 september 2009, an advisory panel recommended that the food and drug administration (fda) of the usa license gardasil in the united states for boys and men ages 9–26 for the prevention of genital warts. soon after that, the vaccine was approved by the fda for use in males aged 9 to 26 for prevention of genital warts and anal cancer. in 2011, an advisory panel for the centers for disease control and prevention (cdc) recommended the vaccine for boys ages 11–12. this was intended to prevent genital warts and anal cancers in males, and possibly prevent head and neck cancer (though the vaccine's effectiveness against head and neck cancers has not yet been proven). the committee also made the vaccination recommendation for males 13 to 21 years who have not been vaccinated previously or who have not completed the three-dose series. for those under the age of 27 who have not been fully vaccinated the cdc recommends vaccination. harald zur hausen's support for vaccinating boys (so that they will be protected, and thereby so will women) was joined by professors harald moi and ole-erik iversen in 2011. older age when gardasil was first introduced, it was recommended as a prevention for cervical cancer for women 25 years old or younger. evidence suggests that hpv vaccines are effective in preventing cervical cancer for women up to 45 years of age. in 2018, the food and drug administration released a summary basis for regulatory action and approval for expansion of usage and indication for the 9-valent hpv vaccine to include men and women 27 to 45 years of age. public health the national cancer institute states "widespread vaccination has the potential to reduce cervical cancer deaths around the world by as much as two-thirds if all women were to take the vaccine and if protection turns out to be long-term. in addition, the vaccines can reduce the need for medical care, biopsies, and invasive procedures associated with the follow-up from abnormal pap tests, thus helping to reduce health care costs and anxieties related to abnormal pap tests and follow-up procedures." as of 2004 preventive vaccines protect against the two hpv types (16 and 18) that cause about 70% of cervical cancers worldwide. because of the distribution of hpv types associated with cervical cancer, the vaccines are likely to be most effective in asia, europe, and north america. some other high-risk types cause a larger percentage of cancers in other parts of the world. vaccines that protect against more of the types common in cancers would prevent more cancers, and be less subject to regional variation. for instance, a vaccine against the seven types most common in cervical cancers (16, 18, 45, 31, 33, 52, 58) would prevent an estimated 87% of cervical cancers worldwide. only 41% of women with cervical cancer in the developing world get medical treatment. therefore, prevention of hpv by vaccination may be a more effective way of lowering the disease burden in developing countries than cervical screening. the european society of gynecological oncology sees the developing world as most likely to benefit from hpv vaccination. however, individuals in many resource-limited nations, kenya for example, are unable to afford the vaccine. in more developed countries, populations that do not receive adequate medical care, such as poor or minorities in the united states or parts of europe also have less access to cervical screening and appropriate treatment, and are similarly more likely to benefit. in 2009, dr. diane harper, a researcher for the hpv vaccines, questioned whether the benefits of the vaccine outweigh its risks in countries where pap smear screening is common. she has also encouraged women to continue pap screening after they are vaccinated and to be aware of potential adverse effects. according to the cdc, in 2012, use of the hpv vaccine had cut rates of infection with hpv-6, -11, -16 and -18 in half in american teenagers (from 11.5% to 4.3%) and by one third in american women in their early twenties (from 18.5% to 12.1%). side effects the hpv vaccine is generally safe with no increased risk of serious adverse effects. hpv vaccines are approved for use in over 100 countries, with more than 100 million doses distributed worldwide. extensive clinical trial and post-marketing safety surveillance data indicate that both gardasil and cervarix are well tolerated and safe. when comparing the hpv vaccine to a placebo (control) vaccine taken by women, there is no difference in the risk of severe adverse events. gardasil is a three-dose (injection) vaccine. as of 8 september 2013, there were more than 57 million doses distributed in the united states, though it is unknown how many were administered. there have been 22,000 vaccine adverse event reporting system (vaers) reports following the vaccination. 92% were reports of events considered to be non-serious (e.g., fainting, pain and swelling at the injection site (arm), headache, nausea and fever), and the rest were considered to be serious (death, permanent disability, life-threatening illness and hospitalization). however, vaers reports include any reported effects whether coincidental or causal. in response to concerns regarding the rates of adverse events associated with the vaccine, the cdc stated: "when evaluating data from vaers, it is important to note that for any reported event, no cause-and-effect relationship has been established. vaers