HPV vaccine

HPV vaccines train the immune system to recognize and fight specific types of human papillomavirus. The first one was introduced in 2006, and there are now three licensed versions: one that targets two HPV types (bivalent), one that targets four types (quadrivalent), and one that targets nine types (nonavalent). All are considered safe and highly effective, or have met standards for immune response. Every vaccine covers HPV types 16 and 18, which cause about 70% of cervical cancer cases worldwide. The quadrivalent vaccine also blocks HPV types 6 and 11, while the nonavalent one adds protection against types 31, 33, 45, 52, and 58. The World Health Organization recommends these vaccines as part of routine immunization in all countries, focusing first on girls aged 9 to 14.

The vaccines are estimated to prevent 70% of cervical cancers, 80% of anal cancers, 60% of vaginal cancers, 40% of vulvar cancers, and more than 90% of HPV-positive oropharyngeal cancers. They also protect against penile cancer and genital warts—quadrivalent and nonavalent vaccines offer near-complete protection against warts. Protection lasts at least five to ten years.

For girls aged 9 to 14, the WHO advises either one or two doses. Girls and women aged 15 to 20 should receive two doses spaced six months apart. Women over 21 should also get two doses with a six-month interval. As of 2022, 21% of girls aged 9 to 14 worldwide had received at least one dose, and 37 countries were using a single-dose schedule that year, reaching 45% of girls in that age group. By September 2024, 57 countries had adopted the single-dose schedule. As of November 2024, at least 144 countries (74% of WHO member states) included the HPV vaccine in their national immunization programs for girls; by 2022, 47 countries (24% of member states) also included boys. High vaccination coverage can create herd immunity, protecting even those not vaccinated.

The HPV vaccine is on the WHO’s List of Essential Medicines. The WHO’s main goal for HPV immunization is preventing cervical cancer, which makes up 82% of all HPV-related cancers—over 95% of cervical cancers are caused by HPV. In 2020, 88% of cervical cancer cases and 90% of deaths occurred in low- and middle-income countries, compared to just 2% in high-income countries. The WHO aims for 90% of girls to be fully vaccinated by age 15.