Mapping the global use of different BCG vaccine strains

Abstract

Bacille Calmette-Guérin (BCG) vaccine is one of the oldest and most commonly administered vaccines worldwide. Different BCG vaccine strains exist as a result of genetic changes that occurred during repeated subculture in different countries before lyophilisation was introduced for storage of seed lots in the 1960s. Increasing evidence suggests that these genetically divergent BCG vaccine strains are associated with different protective efficacy against tuberculosis (TB), different rates of adverse events and variable susceptibility to anti-tuberculous drugs. Information on which BCG vaccine strains are used in each country worldwide has not previously been collated. This report summarises da..