Why in news?
- World Health Organization (WHO) 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.
- Previously, a study found an association between countries that have a universal BCG vaccination and reduced coronavirus cases — and even deaths.
Concerns regarding BCG Vaccine as a COVID-19 Response
- 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.
- 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 beneficial effects of the BCG vaccine given at birth are “unlikely” to reduce the severity of COVID-19 decades later.
- 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 – as it is already known that the virus induces cytokine storm in some patients, leading to further complications
- If not effective against the novel coronavirus, BCG vaccination is likely to give a false sense of security to people.
- Using the vaccine without evidence of its benefits could further jeopardise vaccine supply, which is already short, to protect children against disseminated TB in high-risk countries.
What is BCG Vaccine?
- Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB).
- In countries where tuberculosis or leprosy is common, one dose is recommended in healthy babies as close to the time of birth as possible.
- In areas where tuberculosis is not common, only children at high risk are typically immunized, while suspected cases of tuberculosis are individually tested for and treated.
- Adults who do not have tuberculosis and have not been previously immunized but are frequently exposed may be immunized as well.
- BCG also has some effectiveness against Buruli ulcer infection and other nontuberculous mycobacteria infections.
- Additionally it is sometimes used as part of the treatment of bladder cancer.
- India and Pakistan introduced BCG mass immunization in 1948, the first countries outside Europe to do so.