Indian Council of Medical Research, India’s top body for the formulation, coordination and promotion of biomedical research, said it will start a new trial next week to study the efficacy of anti-TB vaccine BCG in preventing mortality in COVID-19.
The statement comes even as the World Health Organization has said that there is no evidence that the Bacille Calmette-Guérin vaccine is effective in preventing Coronavirus 2019 infections.
Speaking to the media today, Dr Raman R Gangakhedkar, head of ICMR’s epidemiology and communicable diseases division, said it was worth exploring the possibility, given the evidence at hand.
Even the WHO, which has warned against diverting large amounts of BCG vaccine from its traditional use to the fight against COVID-19, has admitted that the vaccine has been found to have “non-specific effects on the immune system” in humans.
Translated into plain English, it means that the vaccine has effects on the immune system that goes well beyond the expected benefit of preventing meningitis, a severe form of TB infection in the brain.
It is this peculiarity, as well as some empirical data, that has led to speculation that the vaccine lowers mortality in COVID-19.
At first glance, empirical evidence seems to suggest that countries with mandatory BCG vaccination programs, such as India and the former constituents of the Soviet Union, have seen noticeably lower death rates from COVID-19 compared to countries such as the US, Italy and Spain, which don’t have such a program. Death rates in these countries are well north of 5%, while it is around 2% in Asia.
Examples of Portugal and former East Germany, both of which have — or used to have till recently — mandatory BCG vaccination programs, are frequently held up by those who argue that the vaccine may be helping the population fight off the virus better.
While Gangakhedkar did not dismiss the possibility, he said ICMR is not, as of today, advocating that anyone — including health workers — should be injected with BCG vaccine as a precaution against COVID-19.
Part of the reason for the skepticism comes from the estimated longevity of the vaccine’s benefits on the human body.
Gangakhedkar said that the vaccine, which is given at birth in most countries including India, has its effect only for 15 years, and children need to be revaccinated at age 15 for continued protection.
At the same time, “some studies have found that if you administer BCG vaccine in some cancer patients, it works as an immunomodulator. Because of this, our body’s natural killer cells can target the cancer cells better,” he said.
“But I doubt that this phenomenon is at work here, because the vaccine gives you protection only for a maximum of 15 years.”
“Some are saying that it might be able to protect you if you do re-vaccination even after 15 years of age. However, the chances of this happening are less,” he said today.
To arrive at a conclusive determination, ICMR is planning a study that will start next week, he said.
“Until we get that data, ICMR will not recommend that BCG vaccine should be given to even health-workers,” he said.
Separately, Gangakhedkar also said that all three major quasi-species or strains of Coronavirus 2019 are in circulation in India as Indian cases have originated from people who brought the virus from China, Europe and other places.
On a positive note, he said, the virus has been found to be relatively stable and does not seem to have undergone large number of mutations in the last three months that it has been in India.
A fast-mutating virus is a nightmare for vaccine- and drug-developers, as there is a high chance that by the time the vaccine or the drug is brought to the market, the virus would have mutated so much that the drug or vaccine will fail to work.