MUMBAI: The debate over the anti-tuberculosis vaccine’s ability to protect against Covid-19 got a fresh lease with an American research paper stating that the BCG ‘slows down’ the infection’s spread within the community—at least in the first 30 days.
The paper published in Science Advances, a peer-reviewed medical journal brought out by the American Association for the Advancement of Science, said that countries with mandatory Bacillus Calmette-Guérin (BCG) vaccination showed “slower infection and death rates” during the first 30 days of the Covid-19 outbreak in their country.
The researchers estimated only 468 people are likely to have died from Covid-19 in the US as of March 29—which is 19% of the actual figure of 2,467 deaths by that date—if it had instituted mandatory BCG vaccination several decades ago.
Countries, such as India and China, which have included BCG in the national immunization programme have had relatively lower death rates. Some sections of doctors believe it is the BCG vaccine that is protecting people against Covid-related complications.
It is known that the BCG vaccination given to babies within 15 days of birth to prevent TB, strengthens immunity against other infectious diseases too. Ever since Covid-19 emerged eight months back, there has been a lot of discussion about BCG’s ability to protect against novel coronavirus as well.
The US study analysed the day-by-day rate of increase of confirmed Covid cases in 135 countries and deaths in 134 countries in the first 30-day period of each country’s outbreak. “Mandatory BCG vaccination correlated with a flattening of the curve in the spread of Covid-19,” the analysis showed. However, the authors said BCG cannot be portrayed as a “magic bullet”.
Public health expert Dr Anant Bhan said that the observation that the BCG vaccine “protects” against Covid-19 seems “more ecological” than scientific. “It seems just conjecture at the moment, especially since both India and Brazil, which have BCG vaccination programmes, have huge numbers of cases at the moment,” he added.
Dr Shashank Joshi, dean of the Indian College of Physicians, said: “BCG is important in building immunity and is believed to have a role in Covid prevention.” Citing examples, he added that while Portugal, which has a mandatory BCG vaccine programme, saw relatively fewer cases, its neighbour Spain witnessed one of the worst outbreaks in the world.
“There are two points of discussion with respect to the BCG vaccine: Can it be given as a repurposed vaccine? Can it be given to a Covid-patient to prevent complications?” said Dr Joshi. The state government is carrying out a clinical trial to check the efficacy of the BCG vaccine in reducing morbidity among Covid-19 patients. “The trial has 250 Covid patients who were treated in 18 medical colleges of the state. An answer should be available within the next two to three months,” he added.