Concerns Over Use of BCG Vaccine: WHO | 02 May 2020

Why in News

The World Health Organization (WHO) has highlighted a few critical issues over the use of BCG vaccine for Covid-19.

• BCG, or bacille Calmette-Guerin, is a vaccine for tuberculosis (TB) disease.

Key Points

• WHO emphasizes 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.
• According to an earlier study, there is an association between countries that have a universal BCG vaccination and reduced coronavirus cases.
  
  • It argues that countries that have deployed the BCG vaccine in their immunisation programmes have seen fewer deaths from Covid-19.
  • The BCG vaccine enhances the innate immune response to subsequent infections which might reduce viral load after Covid-19 exposure, with a consequent less severe Covid-19 and more rapid recovery.
• Views in India:
  
  • According to the Translational Health Science and Technology Institute (THSTI), Faridabad, the vaccine can prevent intracellular infections, so its protective effects against Covid-19 is a biologically plausible hypothesis.
  • It will be premature for India, that has had a consistent TB vaccination policy since 1968, to take comfort from the study.
• Five reasons countries should wait for the results of the BCG vaccine randomised controlled trials:
  
  • The association of fewer Covid-19 cases in countries that have a universal BCG vaccination programme is based on population rather than individual data.
  • The benefits of the BCG vaccine given at birth are unlikely to reduce the severity of Covid-19 decades later.
    
    • The beneficial effects of the BCG vaccine might be altered by subsequent administration of a different vaccine and become less effective after longer periods.
  • There is a remote possibility that the BCG vaccine ramps up the immune system leading to worsening of Covid-19 in a small population of patients with a severe disease.
    
    • Coronavirus induces cytokine storm in some patients, leading to further complications and even death.
  • If BCG vaccination is not effective against the novel coronavirus, it is likely to give a false sense of security to people, especially during the pandemic.
  • Using the vaccine without evidence of its benefits could further jeopardise the already short supply of the BCG vaccine.

Source: TH