HPV vaccines

Human papilloma virus (HPV) vaccines are vaccines that prevent infection by certain types of human papillomavirus. Available vaccines protect against either two, four or nine types of HPV. All vaccines protect against at least HPV types 16 and 18, which cause the greatest risk of cervical cancer. It is estimated that the vaccines may prevent 70% of cervical cancer, 80% of anal cancer, 60% of vaginal cancer, 40% of vulvar cancer and possibly some mouth cancer. They additionally prevent some genital warts, with the vaccines against HPV types 4 and 9 providing greater protection. 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. In those already infected, the vaccines are not effective. 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 2017, 71 countries include it in their routine vaccinations, at least for girls. They are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about US$47 a dose as of 2014. In the United States, it costs more than US$200. Vaccination may be cost effective in the developing world. HPV vaccines are used to prevent HPV infection and therefore cervical cancer. Good evidence supports that vaccination of large percentage of people within a population decreases rates of HPV infections with part of the benefit from herd immunity. Some types are recommended in the United States for women and men who are 9 to 45 years of age. Since the vaccines only cover some high-risk types of HPV, cervical cancer screening is recommended even after vaccination. In the US, the recommendation is for women to receive routine Pap smears beginning at age 21. HPV vaccines have 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 vaccines. The protection against HPV 16 and 18 has lasted at least 8 years after vaccination for Gardasil and more than 9 years for Cervarix. It is thought that booster vaccines will not be necessary.