Despite the government's continued push to raise awareness of a rubella outbreak, only about 8 percent of men age 40 to 47 — who are most vulnerable to being infected — have used coupons for free antibody tests, health ministry data has shown.

The number of rubella cases nationwide declined for the fourth-straight year to 91 in 2017, but in 2018 the figure surged to 2,946. This marked the second-highest level since 2008, when current survey methods began. As of the 38th week of this year, there were 2,196 cases nationwide. Many of the patients were men in their 30s to 50s who did not receive vaccinations as children.

The Health, Labor and Welfare Ministry has decided to make the test for rubella antibodies and vaccinations free, in principle, for men between 40 and 57 years of age for three years through the end of fiscal 2021. As a first step, in the current fiscal year, coupons were to be distributed through local governments to about 6.46 million men born between April 2, 1972, and April 1, 1979. Almost all the coupons have been handed out.