National- and state-level impact and cost-effectiveness of nonavalent HPV vaccination in the United States

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.

Keywords: HPV; cervical cancer; migration; model; vaccination.

Fig. 1.

Current state-specific full-schedule HPV vaccination among adolescent girls (age 13–17 y) in 2014.

Fig. 2.

Impact through 2050 of no vaccination (solid line), 2vHPV/4vHPV continued at current adolescent coverage (long dashed line), 9vHPV at current coverage (short dashed line), 2vHPV/4vHPV at 100% coverage (dotted line), and 9vHPV at 100% coverage (dashed and dotted line) on annual HPV-associated cervical cancers (A) and annual HPV-associated cervical cancer mortality (B).

Fig. 3.

(A and B) QALYs gained and vaccination cost (A) and QALYs gained and total societal cost (including both vaccination and medical costs) (B) associated with a proportion switching to the nonavalent vaccine of 0, 0.25, 0.5, or 1 (vertical contours). (C) The probability that vaccination is cost-effective, as a function of WTP per QALY gained. Adolescent vaccination was evaluated at current coverage (dotted line), with an additional 10% (short dashed line), 20% (double line), 30% (long dashed line), and 40% (dashed and dotted line) of the population vaccinated, and at 100% adherence (dashed and double-dotted line).

Fig. 4.

(A–C) Impact of a national 10% expansion in vaccination coverage above current levels with 9vHPV (horizontal dotted lines) compared with a unilateral 10% expansion by each state (circles) on the nationwide cumulative cancers averted through 2050 per 10,000 vaccines administered (A), the nationwide cumulative deaths averted through 2050 per 10,000 vaccines administered (B), and the incremental cost-effectiveness ratio (C). (D) Of those cancers averted by a unilateral 10% increase in coverage, the proportion that occurs within the borders of the state in which coverage is increased is negatively log-linear with the state emigration rate.

Fig. 5.

From the perspective of each state: Cost per capita (A–C) and QALYs gained per 10,000 population (D–F) if the state unilaterally switches to 9vHPV (A and D) or all states switch to 9vHPV (B and E). C and F show the improvement in each outcome if all states switch to 9vHPV compared with each state unilaterally switching to 9vHPV.