Immunity to measles in the Croatian population.

In the frame of measles elimination activities, sera from 1205 Croatian citizens from all parts of the country and of all ages were tested, using Gull Laboratories ELISA, for measles IgG. Equivocal results were found in 50 subjects. Of the remaining 1155 participants, 118 or 10.2% were negative and 1037 or 89.8% positive. The proportion of seronegatives ranged from zero (age groups 41-50, 51 and more) up to 21.4% (1 year of age). As for their distribution into age groups suggested by the European Regional Office of WHO, there were 12.7, 8.9, 9.5 and 8.8% negatives in age groups 1-4, 5-9, 10-14 and 15 + years, respectively. According to these results, only the first two age groups meet WHO criteria, indicating that vaccination coverage higher than the reported 90-94% should be attained if one is to expect measles elimination.