Diphtheria in Lithuania, 1986-1996

Diphtheria reappeared in Lithuania in 1986 and rose to epidemic levels by 1 992, Between 1991 and 1996, 110 cases of diphtheria were registered, with a n incidence of 0.03-1.15/100,000 population, Most cases (84%) and all 17 de aths occurred among persons greater than or equal to 15 years, most of whom had never been vaccinated. Persons 40-49 years old had the highest average annual age-specific morbidity (1.70/100,000) and mortality (0.53/100,000) rates. Low levels of immunity among individuals 40-49 years old and migrati on to epidemic areas in Russia and Belarus contributed to the epidemic's oc currence. Between 1991 and 1995, toxigenic Corynebacterium diphtheriae stra ins were isolated from 84 of all registered patients (76%), and nontoxigeni c strains were isolated from 13 (12%), By 1996, two mass vaccination campai gns, which provided one dose of vaccine to individuals 25-30 years old and three doses of vaccine to persons 31-60 years old, helped reduce the number of cases. The first campaign achieved 69% coverage; the second achieved 48 % coverage.