The cost-effectiveness of human pappillomavirus vaccines in men : a systematic review

Abstract

Background Human Papillomavirus (HPV) infection is the most common sexually transmitted infection worldwide. It is the leading cause of genital warts and cervical cancer, and is strongly associated with oropharyngeal and other anogenital cancers. To date, two prophylactic HPV vaccines are available, both of which have shown high efficacies in protection against vaccine-type HPV infection and HPV-associated diseases in both males and females. Despite the proven efficacies, male vaccination has not been included in any national vaccination programme worldwide. In Hong Kong, vaccine uptake remains low despite the Department of Health’s recommendation, and a routine comprehensive vaccination programme is yet to be adopted. However, very limited cost-effectiveness data are available to guide policy makers on the economic potential of implementing routine HPV vaccination, especially that of extending vaccination to males. This systematic review is among the first to evaluate the latest cost-effectiveness analyses of HPV vaccination in men and apply the synthesis to the context of Hong Kong, which will help local policy makers in their consideration of implementing a comprehensive HPV vaccination programme in Hong Kong, especially whether to extend vaccination to males.

Methodology A systematic review was conducted to retrieve literatures that provide full economic evaluations of cost-effectiveness analyses of HPV vaccination programmes that included males, by searching in the MEDLINE (Ovid system) using relevant keywords. English articles that provide full economic evaluations of cost-effectiveness analyses of HPV vaccination programmes in men or in both sexes in the age group of 9-45 years were considered as potential studies for inclusion in this review.

Results The literature search identified 117 studies, 107 among them failed to meet the inclusion criteria, 2 were duplicated studies, 1 did not meet the quality assessment criteria described by Drummond et al. A total of 7 studies were included in this review. All studies adopted dynamic models, except one using static model, which did not take into account the effect of herd immunity on HPV transmission. The studies measured the cost-effectiveness using different assumptions on vaccine costs, coverage, efficacies, duration of protection, costing and perspectives. Only several studies took a societal perspective in their analyses and included non-medical and indirect costs. 4 among all studies explored the cost-effectiveness of extending HPV vaccination to males, 2 only focused on female-only HPV vaccination with indirect benefits to males, and 1 only evaluated vaccination of the men who have sex with men (MSM) population. The discrepancies in different costing and outcome measures lowered the comparability of cost-effectiveness analyses. Yet, in general, the studies reported vaccine efficacies and duration of protection to significantly impact the cost-effectiveness of vaccination in both sexes. Moreover, vaccine coverage is critical to influence cost-effectiveness, for male vaccination would only be cost-effective given a female vaccine coverage of 50% or below.

Conclusion and Implications Evidence from recent cost-effectiveness analyses suggested that vaccinating 12-year-olds is cost-effective. School-based immunization programmes are recommended to vaccinate the population at an early age before sexual debut for better clinical and economic benefits. Extending HPV vaccination to boys will be cost-effective when female vaccine coverage is low. Given a low vaccine uptake rate among schoolgirls in Hong Kong, policy makers should consider expanding vaccination to boys when implementing a routine immunization programme by synthesizing findings from epidemiological and economic evaluations.