WHO raises concern over use of BCG vaccine-THE HINDU-02-05-2020

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In a letter published in The Lancet on April 30, World Health Organization Director-General Tedros A Ghebreyesus and others highlight a few critical issues over the use of BCG vaccine for COVID-19. They underscore the importance of randomised controlled trials of the vaccine to understand its safety and efficacy before using it on healthcare workers.

Randomised controlled trials using BCG vaccine are under way in the Netherlands and Australia to find out whether the vaccine can reduce the incidence and severity of COVID-19 among healthcare workers.

The authors do state that the BCG vaccine, which “enhances the innate immune response to subsequent infections, might reduce viral load after SARS-COV-2 exposure, with a consequent less severe COVID-19 and more rapid recovery”.

Second, the beneficial effects of the BCG vaccine given at birth are “unlikely” to reduce the severity of COVID-19 decades later. “One reason for this is that the beneficial off-target effects of the BCG vaccine might be altered by subsequent administration of a different vaccine,” they write.

Third, there is a possibility, even if remote, that the BCG vaccine ramps up the immune system leading to exacerbation of COVID-19 in a small population of patients with a severe disease. The vaccine can prevent intracellular infections.