Diphtheria immunity of Albanian and other eastern European immigrants in Greece compared with the local population - The risk of reemergence in Greece

A large number of immigrants have come to Greece from diphtheria-endemic co untries during the past 8 years. Information on the immune status against d iphtheria among immigrants from Albania and the New Independent States IN I S) of the former USSR, as well as the Creek population, is essential in pla nning public health control measures. The main objective of the study was t o determine the risk of the spread of diphtheria if new cases arrived in th e country. Diphtheria antitoxin (DAT) in sera from 185 healthy individuals from northern Greece and 227 immigrants from Albania and the NIS was titrat ed using a quantitative ELISA test. The participants were adults aged 22 to 46 years, Titers were considered as protective when DAT levels were higher or equal to 0.1 IU/ml. Albanian immigrants exhibited the highest rates of protective titers (99 of 167, 59.3%), while lower immunity rates were detec ted among immigrants from the NIS (20 of 60, 33.3%) (1.5 < OR = 2.9 < 5.4, p = 0.0007) as well as among Creek participants (47 of 185, 25.4%) (2.8 ( O R = 4.4 < 7.0, P = 0.00001). Immunity rates did not differ between Creek an d NIS participants. DAT levels of persons with protective titers differed b etween the three population groups (analysis of variance, p = 0.0005), with the highest mean DAT values detected among NIS immigrants (0.613 IU/ml). F ewer values were found among protected Albanians (0.482 IU/ml) and Creeks ( 0.314 IU/ml). There was no significant age- and sex-related difference in i mmunity rates and DAT levels among the groups. The low immunity rates among Creek adults might suggest that they have had no natural contact with toxi genic strains of corynebacteria. A booster dose of diphtheria toroid for lo cal adults is recommended, to reduce their risk of acquiring toxigenic stra ins from individuals who may carry the bacteria without exhibiting clinical disease.