As the novel coronavirus pandemic spreads through vulnerable sections of populations around the world, with over 15 lakh cases globally, scientists are rushing to find a vaccine for COVID-19. Among several areas of focus—ranging from Ivermectin, which is used to treat head lice, to malaria drugs—is a potential connection between COVID-19 and the Bacillus Calmette–Guérin, or BCG vaccine, a widely–administered vaccine which has been used to immunise infants against tuberculosis for the last 80 years in developing countries. TB, an infectious bacterial disease primarily affecting the lungs, has been around for several millennia, infecting millions each year and endemic in many poor countries. Can the BCG vaccine now be put to use on these new COVID-19 frontlines?
While noting that there is “little evidence yet that the vaccine will blunt infection with the coronavirus,” the New York Times reported last week that a series of clinical trials may answer this question in the coming months. “On Monday, scientists in Melbourne, Australia, started administering the B.C.G. vaccine or a placebo to thousands of physicians, nurses, respiratory therapists and other health care workers — the first of several randomized controlled trials intended to test the vaccine’s effectiveness against the coronavirus,” the article reported. Other scientists are also studying whether there is a correlation between the BCG vaccine and fewer COVID-19 deaths in countries that have previously administered the vaccine.
In developing nations like India which have used the BCG vaccine, this connection is of great interest. Indians have wondered whether their previous use of the BCG vaccine has granted them an increased immunity from COVID-19. However, doctors have said that it is too early to establish a direct link between the BCG vaccine and COVID-19, and that large-scale epidemiological studies are needed before anything can be concluded.
On 8 April, I spoke to Kevin Urdahl, a doctor and a professor at the Center for Global Infectious Disease Research, a research center at the Seattle Children’s Hospital. Urdahl has been researching an effective TB vaccine for over 20 years through the Urdahl Lab, which is also based at the hospital. He offered a reality check on the role that BCG might play in the ongoing COVID-19 research and cautioned that we need to consider the impact of the BCG vaccine on our immune systems before we look at it as a potential safeguard against COVID-19.
Rajni George: Are you talking about the potential connection between COVID and TB in the United States?
Kevin Urdahl: People are talking about coronavirus all the time, that’s all that anyone is talking about. But I wouldn’t say that the connection between TB or BCG and coronavirus comes up much here. I think that part of the reason is that tuberculosis and BCG is much more on the minds of people in India than it is in the United States. We don’t use BCG here, most people don’t know people who are touched by TB, and that’s different in India.