Vaccines for mumps are in short supply across the country due to heavier-than-expected demand, sources say.
Drugmakers have started to notify medical institutions of the situation, although the shortfall is expected to be alleviated between next week and late November, the sources said.
Some medical institutions in the Tokyo metropolitan area and other districts, however, have started to suspend mumps vaccinations altogether.
The number of people wanting mumps vaccinations, which are voluntary, is said to be increasing as more municipal governments grant subsidies to cover part or all of the vaccination cost, the sources said.
Demand is higher than in past years and began to outstrip supply in late September, an official at a major drugmaker said.
Drugmakers produce mumps vaccines after estimating annual demand based on conditions in the previous year. Since production takes time, it is difficult for them to respond to sudden shortages.
Mumps is an infectious disease, with its virus causing parotid inflammation. The disease frequently becomes epidemic from winter through spring among infants and children.
Many medical institutions offer mumps vaccinations throughout the year.
In Japan, Takeda Pharmaceutical Co. and Kitasato Daiichi Sankyo Vaccine Co., a unit of Daiichi Sankyo Co., produce mumps vaccines.