Studies on the epidemiology of child infections in the Bari area. I. Current state of immunity against Coxsackie B viruses.

The presence and titer of neutralizing antibodies against Coxsackie B viruses were investigated in 1,944 children under 15 years of age living in Bari and its area. In 1,781 out of 1,944 sera (91.6%), neutralizing antibodies were present against at least one of the strains tested: 333 (17.1%) samples were found to be positive for one serotype only, 412 (21.2%) for 2 serotypes, 394 (20.3%) for 3, 394 (18.0%) for 4, 199 (10.2%) for 5 and 94 (4.8%) for all 6 strains tested. Of the 1,944 serums examined, 1,043 (53.7%) were found to be positive for type 2, 1,073 (53.3%) for type 5, 991 (51.0%) for type 1, 858 (44.1%) for type 3, 760 (39.1%) for type 4 and 605 (31.1%) for type 6. The rate of positive responses, which was high at birth and in the first months of life (96.7%), diminished between 6 months and 1 year (81.7%) and then rose according to age until it reached 97.7% between 10 and 11 years. After that we observed a considerable reduction in the serological positivities (i.e. 82.3% between 11 and 12 years and 81.5% between 12 and 13 years, respectively).