CELL-MEDIATED-IMMUNITY AFTER MEASLES IN GUINEA-BISSAU - HISTORICAL COHORT STUDY

Objective-To investigate whether children who have had measles have re duced general cell mediated immunity three years later compared with v accinated children who have not had measles. Design-Historical cohort study. Setting-Bissau, Guinea-Bissau. Subjects-391 children aged 3-13 years who were living in Bissau during a measles epidemic in 1991 and still lived there. These included 131 primary cases and 139 secondary cases from the epidemic and 121 vaccinated controls with no history of measles. Main outcome measures-General cell mediated immunity assesse d by measurement of delayed type hypersensitivity skin responses to se ven recall antigens. Anergy was defined as a lack of response to all a ntigens. Results-82 out of 268 cases of measles (31%) were anergic com pared with 20 of the 121 vaccinated controls (17%) (odds ratio adjuste d for potential confounding variables 2.2 (95% confidence interval 1.2 to 4.0); P = 0.009), The prevalence of anergy was higher in secondary cases (33% (46/138)) than in primary cases (28% (36/130)), although t his difference was not significant, Anergy was more common in the rain y season (unadjusted prevalence 31% (91/291)) than in the dry season ( 11% (11/98)) (adjusted odds ratio 4.8 (2.2 to 10.3)). This seasonal in crease occurred predominantly in the cases of measles. Conclusions-Red uced general cell mediated immunity may contribute to the higher long term mortality in children who have had measles compared with recipien ts of standard measles vaccine and to the higher child mortality in th e rainy season in west Africa.