THE RISKS AND BENEFITS OF CHILDHOOD BACILLE CALMETTE-GUERIN IMMUNIZATION AMONG ADULTS WITH AIDS

Objective: To define the risks of disseminated bacille Calmette-Guerin (BCG) or disseminated Mycobacterium tuberculosis in adults with AIDS who were immunized with BCG in childhood. Design: HIV-infected patient s with CD4 < 200 x 10(6)/l were enrolled from five study sites (New Ha mpshire, Boston, Finland, Trinidad and Kenya). Prior BCG immunization was determined and blood cultures for mycobacteria were obtained at st udy entry and at 6 months. Acid-fast bacilli were identified as Mycoba cterium tuberculosis complex (MTBC) using DNA probes. MTBC isolates we re then typed by both IS6110 restriction fragment length polymorphism and polymerase chain reaction/restriction enzyme analysis. Setting: Mo st patients in New Hampshire and Finland were outpatients; most patien ts in Trinidad were inpatients with terminal illness; and most patient s in Kenya were outpatients, although 44 were inpatients with terminal illness. Participants: A total of 566 patients were enrolled, includi ng 155 with childhood BCG immunization; 318 patients had a single stud y visit and culture, and 248 patients had two study visits and culture s. Main outcome measures: Isolation and identification of mycobacteria -from blood cultures. Results: Blood cultures were positive for MTBC i n 21 patients; none were positive for M. bovis BCG, and 21 were M. tub erculosis-positive. In Trinidad, seven (87%) out of eight isolates of M. tuberculosis were indistinguishable by IS6110 typing; BCG immunizat ion was associated with a decreased risk of bacteremic infection with M. tuberculosis (P = 0.05). Conclusions: The risk of disseminated BCC among adult AIDS patients with childhood BCG immunization is very low. Childhood BCC immunization is associated with protection against bact eremia with M. tuberculosis among adults with advanced AIDS in Trinida d.