BCG vaccination among West African infants is associated with less anergy to tuberculin and diphtheria-tetanus antigens

To examine risk factors for anergy. delayed-type hypersensitivity was asses sed among 884 infants participating in a vaccine trial in Guinea-Bissau. Th e infants were skin-tested at 7.5 months of age with a panel of seven intra dermal antigens. Risk factors for anergy to tuberculin or anergy to both th e diphtheria and tetanus antigens were determined in relation to Bacillus C almette-Guerin (BCG) vaccination, diphtheria-tetanus-pertussis (DTP) vaccin ation, and measles vaccination. We found sick children to be more anergic t o tuberculin and diphtheria-tetanus antigens than healthy children (OR = 2. 49 (95% confidence interval 1.40-4.55)). There was a higher prevalence of a nergy to tuberculin in the rainy season than in the dry season (OR = 1.67 ( 1.25-2.23)). Children who had taken antimalarials within the last week had a higher prevalence of anergy to tuberculin (OR = 1.41 (1.02-1.92)). BCG va ccination was significantly associated with less anergy to tuberculin and d iphtheria-tetanus antigens (OR = 0.42 (0.28-0.63), OR = 0.77 (0.60-0.99), r espectively). Children vaccinated with BCG before I month of age were more anergic to tuberculin than children vaccinated after I month (OR = 1.61 (1. 19-2.19)). DTP vaccination was associated with less anergy to diphtheria-te tanus antigens (OR = 0.40 (0.32-0.49)), but not to tuberculin. Children wit h a positive reaction to tuberculin were less likely to be anergic to dipht heria-tetanus antigens (OR = 0.36 (0.26-0.49)) than children with a negativ e tuberculin reaction. Children who were vaccinated with BCG before they re ceived their last DTP vaccine were less anergic to diphtheria-tetanus antig ens (OR = 0.40 (0.16-0.88)) than other DTP-vaccinated children. In conclusi on. current disease. rainy season, age below I month of age at the time of BCG vaccination. and administration of chloroquine or quinimax within the l ast 7 days were risk factors for anergy to tuberculin among 7.5-month-old i nfants. BCG vaccination and a positive tuberculin reaction were associated with a lower prevalence of anergy to both tuberculin and diphtheria-tetanus . Thus. BCG vaccination may contribute to better cell-mediated immune respo nses among infants. (C) 2001 Elsevier Science Ltd. All rights reserved.