A new study from Public Health England (PHE) published in the British Medical Journal Wednesday has found Bacillus Calmette-Guérin (BCG) vaccine may protect against M. tuberculosis (TB) infection, in addition to decreasing progression of TB from infection to disease.

Mycobacterium tuberculosis Image/CDC

Prior to this review, it has been widely accepted that BCG vaccine protects against the most severe forms of disease such as tuberculosis (TB) meningitis in children. This review of existing research indicates BCG vaccine can also protect against an individual becoming infected.

The meta-analysis of 14 studies involving 3,855 participants found that BCGvaccinated children were less likely than unvaccinated children to have evidence of TB infection after exposure. Interferon–gamma release assays (IGRA), which can detect M. tuberculosis infection and discriminate this from prior BCG vaccination, made this analysis possible. Previously skin tests weren’t able to distinguish between TB infection, infection from non TB mycobacterium and the presence of BCG vaccine, which made it impossible to determine if someone who had received the vaccine had been protected against getting TB infection.

Dr Anjana Roy, Senior Scientist for Public Health England and lead study author said:

These results suggest a significant shift in our understanding of how anti mycobacterial vaccines work, and could indicate that not only does BCGvaccine protects against developing active TB disease, but that it also protects against getting infected.

This finding will have implications for the use of BCG in current immunisation programmes as well as in the future development of new improved tuberculosis vaccines. It reinforces the recommendation thatBCG should be given as soon as possible after birth to prevent children from getting infected.

In 2012, there were 8,130 cases of TB reported in England, which is an incidence of 15 cases per 100,000 of the population. England now has the second highest TB rate in Western Europe and if current trends continue, will have more TB cases than the whole of the US within 2 years.