Mathematical Models of Cervical Cancer Prevention in the Asia Pacific Region

This article reports on a model-based approach to estimate averted cervical cancer cases and deaths, disability-adjusted life years (DALYs) and incremental cost-effectiveness ratios (I$/DALY averted) for vaccination of young adolescent girls against human papillomavirus (HPV) types 16 and 18. The authors used population-based and epidemiologic data for 25 countries in Asia (22 GAVI-Alliance eligible countries, Thailand, China and Japan). They found that an absolute reduction in lifetime cancer risk varied across countries, depending on incidence, proportion attributable to HPV-16 and -18, and population age-structure; for example, with 70% coverage, cancer reduction was 57% in Indonesia, whereas in Cambodia, it was 49%.

Screening of women over age 30 three times per lifetime, after vaccinating them as pre-adolescents, is expected to provide an additional 20% to 30% mortality reduction. Of the 22 GAVI-Alliance eligible countries, India, Bangladesh, Vietnam and Indonesia account for 87% of the total DALYs averted. Assuming a cost per vaccinated girl of I$10 ($2 per dose), the cost per DALY averted is less than I$250 in 18 of 22 countries. Assuming a cost per vaccinated girl of I$25, the cost per DALY averted is I$1,360 in China compared with I$250 in Thailand, reflecting the greater number of girls that need to be vaccinated to prevent a death from cervical cancer in China.

For the 22 GAVI Alliance-eligible countries, vaccinating 5 consecutive birth cohorts at 70% coverage would cost over US $500 million versus almost US $1.3 billion at per dose costs of $2 and $5, respectively. Including China and Thailand would add US $251 million to US $1.4 billion at per dose prices of $2 and $12.25, respectively. In the countries they assessed, vaccination of young adolescent girls against HPV-16 and -18 could be very cost-effective if the cost per vaccinated girl is less than I$10-I$25; for it to be affordable, however, even with financing assistance, vaccine prices may need to be even lower.