Systematic review of cost-effectiveness studies of human papillomavirus (HPV) vaccination: 9-Valent vaccine, gender-neutral and multiple age cohort vaccination.

BACKGROUND: The success of human papillomavirus (HPV) national immunization program depends on effective strategies in optimizing the uptake of HPV vaccine. Given the increasing number of economic evaluations, this review was conducted to update the economic evidence on HPV vaccination, by focusing on: (i) 9-valent vaccine compared to bi- or quadrivalent vaccine; (ii) gender-neutral vaccination compared to female only vaccination; and (iii) multiple age cohort immunization compared to single age cohort immunization.

METHODS: Searches were performed until June 2016 using 4 databases: PubMed; Embase; Cochrane Library; and LILACS. The combined WHO, Drummond and CHEERS checklist were used to evaluate the quality of included studies.

RESULTS: Thirty-four studies were included in the review and most of them were conducted in high-income countries. The inclusion of adolescent boys in vaccination program was found to be cost-effective if vaccine price and coverage was low. When coverage for female was above 75%, gender-neutral vaccination was less cost-effective than when targeting only girls aged 9-18 years. Current evidence does not show conclusive proof of greater cost-effectiveness of 9-valent vaccine compared to the older HPV vaccines as the price for 9-valent vaccine was still uncertain. Multicohort immunization strategy was cost-effective in the age range 9-14 years but the upper age limit at which vaccination was no longer cost-effective needs to be further investigated. Key influential parameters identified were duration of vaccine protection, vaccine price, coverage, and discounting rates.

CONCLUSIONS: These findings are expected to support policy-makers in making recommendations for HPV immunization programs on either switching to the 9-valent vaccine or inclusion of adolescent boys' vaccination or extending the age of vaccination.