Article in Japanese

Persistence of serum antibody after second MR vaccine at age 6 and 13

Manami NEGORO¹⁾, Haruna NAKAMURA^1,2), Mizuho NAGAO^1,2), Kiyosu TANIGUCHI^1,2), Shigeru SUGA^1,2), Takao FUJISAWA^1,2)

A two-dose schedule of Measles-Rubella (MR) vaccine was introduced in Japan in 2006 for children aged 12-24 months and one year before entrance to primary school (6 years-old). However, after the nationwide outbreak of measles occurred among teenagers in 2007, a 5-year catch-up campaign began in April 2008, targeting cohorts with MR vaccine aged 13 and 18 years-old. There have been few reports on the persistence of vaccine-induced immunity after a second dose at various ages, including 6, 13 and 18 years-old. Therefore, the enzyme immunoassay (EIA) was used to examine the serum antibody titer of measles and rubella, using two age groups 6 years after the second dose: i. e. 12 and 19 year-olds, who had received a second dose at 6 and 13 years-old, respectively.
The mean antibody titers of measles and rubella were over the value of 8 EIA in both groups. The antibody positive rates tended to be relatively lower in 12 years-olds for both measles and rubella with rubella having a statistically significant difference. The seropositivity level for measles and rubella was well maintained 6 years after the second dose when taken at 13 years-old, but it tended to be lower when taken at 6 years-old. With reduced community transmission of measles and rubella, longer term follow-up might be necessary.

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1) Division of Clinical Research, Mie National Hospital
2) Department of Pediatrics, Mie National Hospital

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Received	June 5, 2016
Accepted	December 8, 2016

29 (1)：3─8,2017