PNAS – Proceedings of the National Academy of Sciences of the United States of America
http://www.pnas.org/content/early/
(Accessed 23 April 2016)

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Biological Sciences – Population Biology:
National- and state-level impact and cost-effectiveness of nonavalent HPV vaccination in the United States
David P. Durham, Martial L. Ndeffo-Mbah, Laura A. Skrip, Forrest K. Jones, Chris T. Bauch, and Alison P. Galvani
PNAS 2016 ; published ahead of print April 18, 2016, doi:10.1073/pnas.1515528113
Significance
Vaccination protects against human papilloma virus (HPV)-induced cervical cancer, but coverage varies markedly across the United States. The nonavalent vaccine produces greater health benefits than the bivalent and quadrivalent vaccines at a lower societal cost. Because of the impact of herd immunity, any expansion in coverage will be much more effective in reducing cancer incidence and healthcare costs if targeted in those states with the lowest coverage. Because of interstate migration and the long duration between HPV infection and resultant cervical cancer, much of the benefit of vaccination will be realized beyond a state’s borders. Therefore, both cervical cancer incidence and expenditure can be substantially reduced if the states coordinate policies to promote expansion of coverage, particularly for the new nonavalent vaccine.
Abstract
Every year in the United States more than 12,000 women are diagnosed with cervical cancer, a disease principally caused by human papillomavirus (HPV). Bivalent and quadrivalent HPV vaccines protect against 66% of HPV-associated cervical cancers, and a new nonavalent vaccine protects against an additional 15% of cervical cancers. However, vaccination policy varies across states, and migration between states interdependently dilutes state-specific vaccination policies. To quantify the economic and epidemiological impacts of switching to the nonavalent vaccine both for individual states and for the nation as a whole, we developed a model of HPV transmission and cervical cancer incidence that incorporates state-specific demographic dynamics, sexual behavior, and migratory patterns. At the national level, the nonavalent vaccine was shown to be cost-effective compared with the bivalent and quadrivalent vaccines at any coverage despite the greater per-dose cost of the new vaccine. Furthermore, the nonavalent vaccine remains cost-effective with up to an additional 40% coverage of the adolescent population, representing 80% of girls and 62% of boys. We find that expansion of coverage would have the greatest health impact in states with the lowest coverage because of the decreasing marginal returns of herd immunity. Our results show that if policies promoting nonavalent vaccine implementation and expansion of coverage are coordinated across multiple states, all states benefit both in health and in economic terms.