[An evaluation of the antidiphtheria protection in the general population]

The assessment of the antidiphtheria protection in healthy population is common for a surveillance system within any National Program of Immunization. Our study is intending to measure the antidiphtheria immunity level in apparently healthy peoples living in the southern Romania. Our study were carried out on 8594 healthy subjects. Sample were stratified by nine age groups being representative for the above mentioned area. The titration of diphtheria antitoxin in our laboratory were performed by passive hemagglutination assay (PHA) and in vivo neutralization test (NT). In our study, we had considered as "protective immunity level" an antitoxin titers equal or above 1/640. The overall prevalence of protected peoples was 88.1% (C.I. 95%: 87.4%-88.8%). The prevalence of protected people against diphtheria decrease by age from 94.5% (1-9 years of age) to 82.4% (60 years and over). We think that overall, our national strategy for diphtheria control is quite efficient, but need to be sustained by specific actions concerning some high risk population groups.