ADVERSE EVENTS ASSOCIATED WITH MMR VACCINES IN JAPAN

The largest nationwide active surveillance of four Measles-Mumps-Rubel la (MMR) vaccines was conducted iri Japan. A total of 1255 pediatricia ns actively participated in the study, which comprised 8.6% of all mem bers of the Japanese Pediatric Society. The total number of registered recipients of MMR vaccines was 38 203. They were arbitrarily given on e of the MMR vaccines produced by three makers (Takeda, Osaka city, Ki tasato Minato-ku, Tokyo and Biken Suita city, Japan) or the standard M MR vaccine made of designated strains (Kitasato's measles-AIK-C, Biken 's mumps-Urabe Am9 and Takeda's rubella-To336) produced by Takeda, Kit asato and Biken and were observed for 35 days. The rates of virologica lly confirmed aseptic meningitis per 10 000 recipients were 16.6, 11.6 , 3.2 and 0 for the standard MMR, Takeda MMR, Kitasato MMR and Biken M MR vaccines, respectively. The incidence of convulsions between 15 and 35 days was the highest with the standard MMR vaccine and the inciden ce of fever associated with vomiting occurring between 15 and 35 days (symptoms relevant to aseptic meningitis) were also the highest with t he standard MMR vaccine. The incidence of parotid swelling was the low est with Takeda MMR vaccine. This surveillance revealed that incidence s of aseptic meningitis after administration of the standard MMR vacci ne and of Biken MMR vaccine were different. This posed questions about the manufacturing consistency of the Urabe Am9 mumps virus vaccines. On the other hand, the National Institute of Health found that the bio logical characteristics of the Urabe Am9 mumps virus contained in the standard MMR vaccine and in the Biken MMR vaccine were different. The Biken Company reported that the mumps vaccine in the standard MMR vacc ine was a mixture of two Urabe Am9 mumps vaccine bulks; one identical to that contained in the Biken MMR vaccine and the other produced by a different manufacturing process.