Current Challenges and Future Directions for RSV Prevention Strategies in Japan

Area of Science:

• Pediatrics
• Infectious Diseases
• Public Health

Background:

• Respiratory syncytial virus (RSV) is a major cause of infant lower respiratory tract infections.
• RSV seasonality in Japan has shifted, with summer peaks now observed in northern regions like Hokkaido.
• New prevention tools, nirsevimab and a maternal vaccine, are now available in Japan.

Purpose of the Study:

• To analyze the changing epidemiology of RSV in Japan.
• To evaluate the accessibility and implementation challenges of new RSV prevention tools.
• To propose optimized, equitable strategies for infant RSV protection in Japan.

Main Methods:

• Analysis of RSV epidemiological data in Japan, noting seasonal shifts.
• Review of current policies and reimbursement structures for nirsevimab and maternal RSV vaccines.
• Development of a risk-based, season-independent prevention strategy proposal.

Main Results:

• RSV outbreaks in Japan, particularly Hokkaido, increasingly peak in summer, deviating from traditional winter patterns.
• Access to maternal vaccines is limited by out-of-pocket costs, and nirsevimab reimbursement is restricted to high-risk infants during the RSV season.
• A proposed strategy involves maternal vaccination after 28 weeks gestation and nirsevimab for unvaccinated or preterm infants.

Conclusions:

• Equitable access to RSV prevention in Japan requires policy and system-level improvements.
• Adapting implementation strategies to Japan's evolving RSV epidemiology is crucial for infant protection.
• Japan's experience offers valuable insights for global RSV prevention planning amidst changing transmission patterns.