TOKYO (Kyodo) -- The coverage rate of maternal vaccination against respiratory syncytial virus stood at 11.6 percent in Japan due to the high out-of-pocket payment and a lack of awareness following its introduction in the country in May 2024, according to a national health institute.

The RS virus is a major cause of acute lower respiratory infections in children, and immunizing pregnant women provides protection for their newborns through transplacental antibody transfer.

A research team led by the National Center for Child Health and Development conducted a nationwide survey of women who had given birth between July 2024 and August 2025 ahead of the planned start of free vaccinations in April. The vaccination rate compares with around 30 to 50 percent in the United States and Britain, it said.

Among the 1,279 respondents, 87.2 percent of the vaccinated said that the fee, about 30,000 yen ($190) to 40,000 yen, was expensive, according to the online survey.

At the same time, 28.9 percent of unvaccinated people said they were not aware of the benefits of the vaccine, while 27.3 percent said they were unaware of the vaccine itself. A total of 77.5 percent said they would have been vaccinated if it had been free.

The survey also showed that people with higher household income and levels of education have higher vaccination rates.

The team led by Yusuke Okubo, chief of life course epidemiology division at the center, has published the results of the survey in the Journal of Infection and Chemotherapy under the title "Coverage and determinants of maternal RSV vaccination in Japan: A nationwide survey."