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.