IMMUNITY TO DIPHTHERIA IN NORTHERN NORWAY AND NORTHWESTERN RUSSIA

A case of diphtheria, which has not been seen in Norway for 30 years, was reported in 1992 in the northern part of the country bordering Rus sia. An increasing number of cases of diphtheria has been reported in the former USSR, including the northwestern part of Russia. In order t o elucidate the potential of an epidemic spread across the Norwegian-R ussian border, a seroepidemiological study was performed. A total of 4 70 sera, 243 from Finnmark, Norway, and 227 from Arkhangelsk, Russia, were examined for antibodies against diphtheria toxin, using an in vit ro toxin neutralisation method. No statistically significant differenc e in the presence of diphtheria antitoxin between the Norwegian and th e Russian populations was found. The presence of neutralising antibodi es decreased by age, and this decrease was most pronounced among the R ussians. Individuals aged 40 to 70 years, and Norwegian women in parti cular, seem to have an increased risk for diphtheria as judged by the diphtheria antitoxin levels.