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HPV vaccine

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Human papillomavirus (HPV) vaccines are medical tools designed to provide acquired immunity. This means they help the body learn to recognize and fight specific types of the human papillomavirus. These viruses are significant because they can lead to several types of cancer. The most common concern is cervical cancer, which occurs in the cervix. The World Health Organization (WHO) includes these vaccines on its List of Essential Medicines. This status shows they are vital for global public health.

HPV-vaccine- Gardasil2016JAPAN
HPV-vaccine- Gardasil2016JAPAN

There are currently six licensed HPV vaccines available. They are categorized by how many virus types they target. Bivalent vaccines protect against two types of HPV. Quadrivalent vaccines provide protection against four types. The nonavalent vaccine is the broadest, protecting against nine different types.

HPV Vaccine Gardasil 9 box
HPV Vaccine Gardasil 9 box

All licensed vaccines protect against HPV types 16 and 18. These two specific types are responsible for about 70% of cervical cancer cases globally. The quadrivalent versions also protect against types 6 and 11. These two types are known to cause genital warts. The nonavalent vaccine adds protection against types 31, 33, 45, 52, and 58.

These vaccines are highly effective at preventing various diseases. They may prevent 70% of cervical cancer cases and 80% of anal cancer. They also show 60% effectiveness against vaginal cancer and 40% against vulvar cancer. Interestingly, they are more than 90% effective in preventing HPV-positive oropharyngeal cancers. These are cancers located in the throat area. The vaccines also protect against penile cancer. For genital warts, the quadrivalent and nonavalent vaccines provide virtually complete protection. However, these vaccines do not treat existing infections or cancers.

Since the first HPV vaccine became available in 2006, science has advanced. Researchers have studied how long the protection lasts. For Gardasil, protection against types 16 and 18 lasted at least eight years. Cervarix has shown protection for more than nine years. Scientists believe that booster shots may not be necessary. Recently, a 2025 study looked at Tanzanian girls vaccinated at ages 9–14. After 60 months, at least 99% remained seropositive for HPV-16. This means their bodies still showed signs of immunity after five years.

Vaccination schedules depend on the age of the person receiving the shot. The WHO recommends a one or two-dose schedule for girls aged 9–14. The same schedule applies to girls and women aged 15–20. For women older than 21, two doses are given with a six-month interval. In the United States, the CDC recommends two doses for those under 15. Those aged 15 and older in the US typically require three doses. A single-dose schedule is a newer development from around 2022. This is used in 57 countries as of September 2024.

Global efforts to distribute the vaccine are growing. As of November 2024, at least 144 countries included the vaccine in national plans. This represents at least 74% of WHO member states. By 2022, 47 countries also included boys in their programs. The primary target is usually adolescent girls aged 9–14. This is because vaccination is most effective before they become sexually active. The WHO aims for 90% coverage of girls by age 15.

coverage of the human papillomavirus vaccine, World, 2024 (cropped)
coverage of the human papillomavirus vaccine, World, 2024 (cropped)

Cervical cancer impacts different parts of the world in different ways. In 2020, 88% of cases occurred in low- and middle-income countries. These regions account for 90% of all cervical cancer deaths. In contrast, high-income countries account for only 2% of deaths. In the United States, the vaccine has already shown great success. By 2012, infection rates for types 6, 11, 16, and 18 dropped by half in teenagers. Vaccinating many people also creates herd immunity. This helps protect even those who are not vaccinated.

Even with vaccination, medical follow-ups are still very important. The vaccines do not cover every single high-risk type of HPV. Because of this, cervical cancer screening is still required. For example, women in the US are encouraged to have Pap smears starting at age 21. In Australia, doctors now use HPV DNA testing for screening. This method is the preferred way according to the WHO. Screening helps catch any changes that the vaccine might not have prevented.

HPV Vaccination and Cervical Cancer Incidence A Global Perspective (2021)
HPV Vaccination and Cervical Cancer Incidence A Global Perspective (2021)
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File:coverage of the human papillomavirus vaccine, World, 2024 (cropped).svg
coverage of the human papillomavirus...
File:HPV Vaccine Gardasil 9 box.jpg
HPV Vaccine Gardasil 9 box.jpg
File:HPV-vaccine- Gardasil2016JAPAN.jpg
HPV-vaccine- Gardasil2016JAPAN.jpg
File:HPV Vaccination and Cervical Cancer Incidence A Global Perspective (2021).png
HPV Vaccination and Cervical Cancer...
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