Rise in rubella cases in Japan may indicate outbreak

18 May, 2004
 

The Japanese Health, Labor and Welfare Ministry has received a growing number of reports nationwide of people contracting German measles this year, prompting the implementation of further preventative measures.

Babies born to women infected during the early stages of pregnancy can suffer congenital rubella syndrome-a condition that can cause heart problems and other disorders.

The number of adults and middle and primary school students catching the disease in Ota, Gunma Prefecture, and neighboring areas began rising in November.

A report filed with the prefectural government May 9 numbered the cases at 1,126.

The Ota municipal government has distributed flyers calling on people to take precautionary measures.

As the number of infected people continued to rise even in April, officials at the prefectural government's health division said it might not be possible to contain an outbreak.

Outbreaks of German measles tend to occur every five years.

Previously, only female middle school students were vaccinated periodically, but in 1995, the government lowered the age bracket to between 1 and 7 years old and included boys.

There have been no major outbreaks since 1999, largely due to the increased number of vaccinations given to infants.

According to surveys conducted at 3,000 pediatric medical facilities across the nation, the number of infected people each year since 2000 has remained at about 3,000.

However, the number of cases of infection rose this year in Gunma, Saitama, Oita and Kagoshima prefectures.

According to hospital surveys conducted this year until April 18, the number of patients totaled 1,695, more than 60 percent higher than last year.

In addition, over the past two years, only two children suffered congenital rubella while this year so far, three already have contracted it.

The ministry instructed prefectural governments April 9 to prepare for a possible outbreak of the disease and urged them to gather information on the extent of the spread.

Yuki Tada, head researcher at the Infectious Disease Surveillance Center (IDSC) of the National Institute of Infectious Diseases, pointed out that this year's contraction rates for children aged between 10 and 14 and people more than 20 years old were high compared with previous reports.

Eighty percent of patients suffering from German measles previously were primary school students in the lower grades, but this year, more than 40 percent of those infected have been children older than 10 years.

The reason for the low number of cases among adults as compared with children is not known.

Only about 50 percent of women between 16 and 25 were vaccinated.

The patients that were included in the report to the ministry were diagnosed at special pediatric medical facilities.

It does not include adults treated within medicinal departments of hospitals and those suffering from only light symptoms that were not noticed during medical examinations. Therefore, the real number of adults infected this year is not available.

In Greece, a fall in vaccination rates below 50 percent resulted in an outbreak in 1993 among adults as well as children for the first time in 40 years.

Twenty-five people suffered congenital rubella syndrome in the country.

In Japan, most men aged 25 or older have not been vaccinated.

"Husbands and children are usually the ones who transmit the virus to families. Children should be vaccinated at an early stage, and men should be vaccinated, too," Tada said.

Atsushi Miyazaki Yomiuri Shimbun Staff Writer
From: http://www.yomiuri.co.jp