A pharmacoeconomic study of post-exposure prophylaxis strategies for influenza virus infections in Japan

Background Vaccines can prevent influenza (flu) infections and are cost-effective for society and healthcare. However, the cost-effectiveness of post-exposure prophylaxis as a follow-up strategy is unclear. This study evaluates the cost–utility of post-exposure prophylaxis and treatment strategies with neuraminidase inhibitors (NIs) and a cap-dependent endonuclease inhibitor (EI) for flu infections from the perspective of healthcare costs in Japan. 

Research design and methods A base-case analysis was used to compare oseltamivir, zanamivir, and laninamivir for Nls and baloxavir marboxil for EI. The costs of the first visit to a physician and pharmacy were excluded because of out-of-pocket for post-exposure prophylaxis in Japan. Direct medical costs included the second physician visit, pharmacy and hospital admission expenses, and drug prices, based on the 2020 Japanese Medical Fee Index. EQ-5D-5L questionnaires were utilized to measure healthy participants’ quality of life scores, with a time horizon of 14 days. Deterministic and probabilistic sensitivity analyses were conducted.

Results We find baloxavir marboxil as the post-exposure prophylaxis agent and laninamivir as the treatment agent to be the most cost-effective strategy in Japan, followed by oseltamivir as the post-exposure prophylaxis agent and zanamivir as the treatment agent.

Conclusions The study concludes that baloxavir marboxil and oseltamivir are cost-effective prophylactic agents for flu from the perspective of healthcare costs in Japan. The strategy of baloxavir marboxil as the post-exposure prophylaxis agent and laninamivir as the treatment agent is the most cost-effective in Japan.