Nine-Valent HPV Vaccine Protects Against Additional Oncogenic Strains

By Anna Wald, MD, MPH

The new, nine-valent vaccine against human papillomavirus (HPV) shows nearly 100% efficacy against disease caused by five additional HPV strains, a New England Journal of Medicine study finds.

Industry-funded researchers randomized over 14,000 young women to receive the quadrivalent vaccine (which protects against HPV 6, 11, 16, and 18) or the nine-valent product (which also protects against types 31, 33, 45, 52, and 58).

Among women who were HPV-negative at study entry, the nine-valent vaccine prevented over 96% of high-grade cervical, vaginal, or vulvar neoplasia or cancers related to the five additional strains. Antibody titers against the four original strains were similar in the two groups, suggesting that protection against these viral types was not compromised by the additional antigens.

The successful addition of five more HPV types to the vaccine should extend the prevention of HPV-related cervical cancer to 90%. Coverage in the U.S. remains problematic, however, with only 57% of eligible girls having received one or more dose of HPV vaccine. Reasons include lack of insurance coverage, inconvenience of the three-dose regimen, limited wholehearted support from pediatricians, and moral and religious attitudes in certain parts of the country. The FDA's approval of the nine-valent vaccine raises new questions: What will the product cost? Will it be for girls only? What about those girls who have already begun the quadrivalent vaccine series? We await further guidance from the Advisory Committee on Immunization Practices.

Dr. Wald is an associate editor with NEJM Journal Watch Women's Health, from which this story was adapted.