The government said Tuesday it will offer free rubella vaccinations for three years to men who were unvaccinated in their childhood amid an outbreak of the disease that threatens to dampen demand for travel to Japan.

Rubella can have serious health impacts on unborn babies, and vaccinations and antibody tests will be offered free, in principle, through March 2022 for men aged between 39 and 56 who were not vaccinated under regular public programs.

The number of rubella patients in Japan has reached 2,454 this year, topping the figure for 2012 when the previous outbreak began, and the spread is believed to be mainly caused by unvaccinated men in the targeted age group. Tests and vaccinations will be administered at medical institutions in residential areas from early next year.