In the United States, routine vaccination against human papillomavirus (HPV) is recommended for adolescents aged 11-12 years, and catch-up vaccination is now recommended for both males and females up to age 26 years.
Although an HPV vaccine has been licensed for use up to age 45 years in the United States, the health impact and cost-effectiveness of HPV vaccination for older individuals are unclear.
A study published in PLOS Medicine, by Jane Kim of Harvard University, United States and colleagues suggests that HPV vaccination of men and women over age 26 years provides limited health benefits at a high cost.
To inform national guidelines on expanding HPV vaccination beyond age 26 years, researchers utilised two mathematical models - from Harvard University and Cancer Council New South Wales, Australia - that simulated HPV infection and cervical cancer, as well as six noncervical HPV-related cancers and genital warts.
Using these models and data from the United States, they projected the lifetime costs, benefits, and cost-effectiveness of extending HPV vaccination to both women and men up to age 45 years.
To determine long-term outcomes associated with extending HPV vaccination to people up to age 45 years, the authors projected the lifetime health and economic consequences for vaccinated and unvaccinated older adults taking into account historical HPV vaccination in younger cohorts and current cervical cancer screening among women.
The researchers calculated the medical costs of vaccination, cervical cancer screening, and HPV-related diseases in U.S. dollars and estimated health benefits using quality-adjusted life years.
Findings from both models suggest that HPV vaccination beyond age 26 years has limited health benefits and is not cost-effective, even when making favourable assumptions about vaccine effectiveness and duration of protection in both adult males and females.
The study has several important limitations, however, including the potential changes in the disease burden of noncervical cancers over time.
The authors pointed to a lack of trial data on vaccine effectiveness for males older than 26 years and noted that future studies will be needed for more accurate assessments of health outcomes in older populations receiving HPV vaccine.
According to the authors, "The results from our two independent models suggest that HPV vaccination for adult women and men aged over 26 years is unlikely to represent good value for money in the US."
The study results reported here contributed to the recommendations of the Advisory Committee on Immunization Practices to not recommend catch-up vaccination beyond age 26 years given the limited public health benefit, and recommending instead shared clinical decision making in individuals aged 27-45 years.