Thirty-one children were born with congenital rubella syndrome in Japan in 2013, the worst on record, reflecting a rubella epidemic that started around the beginning of the year, the National Institute of Infectious Diseases said Tuesday.
The number more than tripled from the 2004 record of 10 and was far beyond the zero to four cases reported in other years since the institute began compiling such statistics in 1999.
Thirteen cases of congenital rubella syndrome (CSR) were in Tokyo and five in Osaka, followed by three in Kanagawa Prefecture. Cases were also reported in Tochigi, Saitama, Chiba, Aichi, Mie and Wakayama.
In many of the cases, the mothers had never been vaccinated for rubella or were unsure whether they had been vaccinated, according to the institute.
CRS can occur in a developing fetus if the mothers contracted the rubella virus during pregnancy without having immunity against it. Notable symptoms include congenital heart diseases, hearing impairment and cataracts.
In 2013, the number of rubella patients in Japan soared to about 14,000, some six times more than the year before. An increase in infections tends to boost CRS cases, according to the institute.
Because women cannot receive rubella vaccinations during pregnancy, the health ministry is urging women who are planning to have a child and people around them to receive vaccinations beforehand if they do not have a sufficient level of immunity.