Serum levels of measles IgG antibody activity in children under 5 years inDar-es-Salaam, Tanzania

Measles IgG antibody levels were estimated in sera from 685 Tanzanian child ren, 374 (54.6%) boys and 311 (45.4%) girls aged 18 months to 5 years, usin g an enzyme-linked immunosorbent assay (ELISA). The children were screened for HIV-1 and 2 antibodies using ELISA, and reactive sera were confirmed by Western blot. Nutritional status was assessed by anthropometry. Overall me asles vaccination coverage was 98.8%. Measles antibody activity was not det ected in 41 (6.0%) children, and ten (1.5%) had antibody levels below 200 m IU/ml, the cut-off level considered to be protective. The non-reactive samp les were from one unvaccinated child, one child with unknown vaccination st atus and 39 vaccinated children. Measles IgG antibody levels were higher in girls (3452.1 mIU/ml) than in boys (2928.2 mIU/ml) (p = 0.02). Higher mean levels were found in children with a history of low birthweight (<2.5 kg) (p = 0.03). There were no significant differences in measles antibody level s with regard to variations in nutritional status. No correlation (r(2) = 0 .002) was found between antibody levels and time elapsed since vaccination. In a multivariable logistic regression analysis, children who were HIV-ser opositive (n = 9) were more likely to have non-protective antibody levels < 200 mIU/ml (OR = 5.85; 95% CI: 1.37-24.93).