Exploring the knowledge and attitude toward respiratory syncytial virus vaccine and associated factors among pregnant women in Japan during the early post-marketing phase.

Background: Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections and bronchiolitis in infants. A recently introduced maternal RSV vaccine is highly effective in reducing severe illnesses and could play a key role in preventing RSV infections in infants. However, vaccine hesitancy remains a global issue, and the knowledge and attitude toward RSV vaccines among pregnant women during the post-marketing phase are unclear. Therefore, this study aimed to identify the knowledge and attitude toward RSV vaccine and associated factors among pregnant women in Japan during the early post-marketing phase.

Methods: This exploratory cross-sectional study utilized data from a large-scale nationwide Internet survey conducted in Japan. Pregnant women were provided with five statements related to knowledge of RSV and vaccine against it, including clinical picture and vaccine eligibility, and questions to assess their willingness to be vaccinated. Modified Poisson regression analysis was performed to identify factors associated with willingness to be vaccinated. Independent variables included sociodemographic factors, general vaccination readiness, and knowledge level.

Results: Among 300 pregnant women, 13.3 % expressed willingness to be vaccinated. Participants with knowledge of all five statements accounted for 8.3 %, whereas 40.0 % had no knowledge of RSV or the vaccine. High general vaccination readiness (prevalence ratio [PR] [95 % confidence interval (CI)]:2.02 [1.14-3.58]) and high knowledge levels (PR [95 % CI]: 1.20 [1.03-1.39]) were significantly associated with willingness to be vaccinated.

Conclusions: Willingness to be vaccinated during the early post-marketing phase appeared to be very low, and general vaccination readiness and their level of knowledge were positively associated with this intention. Participants with comprehensive knowledge were approximately 2.49 (= 1.20) times more likely to express willingness to be vaccinated than those with no knowledge. Increasing the awareness of RSV and improving vaccination readiness may be crucial for promoting RSV vaccine acceptance.