Bacillus Calmette-Guérin (BCG) vaccine adverse events in Victoria, Australia: analysis of reports to an enhanced passive surveillance system.

Background: Bacillus Calmette-Guérin (BCG) vaccine is used worldwide, with high efficacy against childhood Mycobacterium tuberculosis (TB) meningitis and miliary TB. BCG vaccine is considered safe, with serious systematic adverse events following immunization (AEFI) of immunocompetent recipients being rare, although adverse event rates vary between differing BCG strains. In Victoria, Australia, AEFI are reported to SAEFVIC (Surveillance of Adverse Events Following Vaccination In the Community), an enhanced passive surveillance system operational since 2007.

Objective: To describe the epidemiology of reported BCG AEFI in Victoria, Australia, particularly following the 2012 recall of Connaught BCG vaccine, substitution with Denmark-SSI vaccine and subsequent programme delivery adjustments.

Methods: Retrospective analysis of reported BCG AEFI in Victoria, Australia, for the 6-year period 2008-2013. Incidence rates were calculated using available doses-distributed, doses-administered and population data denominators with 95 % confidence intervals.

Results: The predominant BCG AEFI reported were abscess and lymphadenopathy, with higher reports for males than for females (p = 0.039).The rates of AEFI per 10,000 doses distributed were similar for the Connaught and Denmark-SSI strains, at 11.6 and 15.4, respectively (p = 0.414). When doses administered rather than doses distributed were considered, the rate of reported Denmark-SSI AEFI was much higher, at 62.8 per 10,000 doses administered. Meaningful result interpretation was hampered by a lack of a BCG vaccination register, multiple disparate providers and absent doses-administered data prior to the recall.

Conclusion: Effective AEFI surveillance is of paramount importance as countries are faced with unplanned vaccine strain changes following the 2012 BCG recall and subsequent global vaccine supply shortages. The Australian experience and lessons learned serve as a timely reminder to BCG vaccination programmes worldwide to review AEFI surveillance systems.