COMPARISON OF GELATIN PARTICLE AGGLUTINATION AND HEMAGGLUTINATION INHIBITION TESTS FOR MEASLES SEROEPIDEMIOLOGY STUDIES

The prevalence of measles antibody in Japan was surveyed with a newly developed gelatin particle agglutination (PA) test, and the results co mpared with those of the hemagglutination inhibition (HI) test. The tw o age-distribution curves of the PA antibody-positive rates at greater than or equal to 1:8 and greater than or equal to 1:32 were almost th e same in all the age groups, except the less-than-1-year-old group fo r which the rate at greater than or equal to 1.8 was higher than that at greater than or equal to 1:32 (p < 0.05, chi(2) test). In the vacci nated children, all groups older-than-1-year of age had antibody-posit ive levels of 96% or more. In contrast, in the unvaccinated children, there was a sharp increase in antibody-positive rates between the 1- a nd 4-year-old groups, indicative that about 80% of the children were i nfected by wild measles virus at these ages. A significant number of P A antibody-positive specimens were antibody-negative (< 1:8) by HI. Th e percentage of specimens in this category, PA (+) but HI (-), was gre atest in infants less than one year old, and least in young children, but it increased with age to 97% of the HI (-) specimens from adults o f more than 20 years of age. The PA test therefore detected some measl es antibodies that HI could not. This test is simple and useful for ma king serosurveys in both developed and developing countries.