Setting: University hospital in Lusaka, Zambia.
Objective: To determine the effects of childhood bacille Calmette-Guerin (BCG) immunization and human immunodeficiency virus (HIV) infection on dual skin test reactions to purified protein derivative (PPD) and Mycobacterium avium sensitin (MAS) in a developing country.
Design: Descriptive cross-sectional study.
Results: Dual skin testing was performed on 112 adults, 58 HIV-positive and 54 HIV-negative. Forty-seven (42%) of 112 had PPD reactions > or =10 mm and 52 (46%) had MAS reactions > or =10 mm. PPD reactions > or =10 mm were present in 30 (63%) of 48 BCG-positive subjects compared to 17 (27%) of 64 BCG-negative subjects (P<0.001). Nineteen (33%) of 58 PPD or MAS skin test positive subjects were PPD dominant, 15 (26%) were MAS dominant, and 24 (41%) were non-dominant. MAS dominant and non-dominant reactions were significantly reduced in HIV-positive subjects, and non-dominant reactions were increased in BCG-positive subjects.
Conclusions: Childhood BCG immunization is associated with PPD reactions > or =10 mm among adults. Reduced PPD reaction rates in HIV-positive adults appear to be due to a loss of BCG-induced PPD reactivity. Prior infection with M. avium complex is detectable in a significant proportion of adults in a developing country.