Serious adverse events associated with Bacille Calmette-Guerin vaccine in Canada

Background: Targeted Bacille Calmette-Guerin (BCG) vaccination is offered to neonates in some First Nations and Inuit (FNI) communities in Canada. Serious adverse events associated with BCG vaccine prompted a review to assess causality. Methods: The Immunization Monitoring Program Active (IMPACT), a pediatric hospital-based active surveillance network, reported admissions for BCG-related adverse events between 1993 and April 2002. The Canadian Advisory Committee on Causality Assessment (ACCA) reviewed the reports to assess causality. Data between 1987 and September 2002 from the Vaccine-Associated Adverse Event Surveillance (VAAES) Program, a passive national reporting system, were also reviewed. Results: IMPACT identified 21 pediatric cases; 19 were Canadian-born, and 18 were FNI. Six disseminated BCG cases were identified; 5 were FNI infants who subsequently died. All had immunodeficiencies and concurrent infections. Other adverse events included 2 cases of osteomyelitis, BCG abscesses and lymphadenitis. ACCA reviewed the 21 cases and determined that 14 were very likely associated with the vaccine, including the 6 disseminated BCGs; 5 were probably associated and 1 was possibly associated with the vaccine; 1 was unclassifiable. The VAAES program identified 157 adverse events. No additional serious systemic adverse events (disseminated BCG or osteomyclitis) were identified. Conclusions: Serious BCG vaccine-associated complications continue to occur in Canada. The numbers of FNI children with disseminated disease was greater than expected from reported rates in the literature.