[Misuse and or overdose of BCG vaccine: evaluation over a 4-year period]

The inappropriate use of BCG vaccine could be followed by adverse events (AE). In order to know their frequency and type, we evaluated the spontaneous reports of misuses (MS) and overdosages (OV) over a 4-year period. One hundred and twenty-six notifications were collected; 109 concerned MS, 13 OV, and 4 concerned both MS and OV. We recorded a high number (97) of MS related to the injection of a BCG vaccine instead of a tuberculin test (TT). Among the 126 initial notifications, 122 cases of AE were reported, 107 after an MS, 11 after an OV and 4 after both MS and OV. The most common AE were related to injection-site reactions which were in fact expected reactions when BCG is used under correct conditions. In half of the cases systemic signs were associated. The most common were asthenia, fever and lymphadenopathy. Seven cases related to MS were considered as serious according to the ICH definition. Six of them recovered, for one the outcome was unknown. It appeared that perhaps the presentation of the products BCG vaccine and TT could play a role in contributing to this inappropriate use. Both presentations contain 10 doses but there are significant differences in colours used and in specific instructions. Despite the fact that the AE reported after an MS and/or an OV represented the one-third of the total notifications recorded with the BCG vaccine over the 4-year period under review, they have to be considered in light of the 170 million doses distributed in 150 countries. We have to consider the possibility of under reporting because of the delicacy of incorrect administration and differences in pharmacovigilance structures worldwide. Even if the number of AE is low, MS and OV should be reported and documented for good pharmacovigilance surveillance.