RESUMEN
Objective. To determine the pre-campaign level of measles seropositivity and to evaluate the effect of a mass measles vaccination campaign on measles seroposivity among primary school children in Denizli, Turkey. Methods. The study was completed in two socioeconomically different areas of Denizli, Turkey, with a sample size of 520 students. One primary school from each area and one classroom from each grade were randomly included in the sample. Before and 2-months after the measles mass vaccinations, blood samples were collected from the students and measles specific IgGs were studied. Results. The pre-campaign overall seropositivity was 74.7%. Post-campaign overall seropositivity increased to 96.5%. Precampaign seropositivity among 8-graders was significantly lower than that in other grades (57.5%, p<0.001) and the difference was explained by the number of vaccinations 8-graders received. Except for the number of vaccination doses, other factors did not have any effect on seropositivity. Conclusions. The mass measles vaccination programs have a potential to control measles for developing countries. In addition, more than one dose of measles vaccination is required for developing countries.