Medical researchers in India have found that the BCG (Bacille Camerin Guerin) vaccine which is used to protect children from tuberculosis can also enhance in the elderly multiple arms of the immune system that might protect them from the coronavirus disease.

A study by the Indian Council of Medical Research has found that the BCG vaccine enhanced innate and adaptive components of the immune system, including memory elements, bolstering evidence for arguments that this familiar vaccine could be tool against Covid-19.

Innate immunity relies on cells already present in the body such as dendtric cells while adaptive immunity involving so-called T-cells and B-cells is triggered by the body’s exposure to microbes.

Scientists at the ICMR-National Institute of Research in Tuberculosis, Chennai, who conducted the study have cautioned that whether their findings translate into protective immunity against SARS-COV-2, the virus that causes Covid-19, is yet to be determined.

But their findings add new evidence to show that the BCG vaccine boosts immune responses in elderly populations just as they do in children and might train the immune system to fight infections other than TB.

“This is very encouraging – it lends support to ongoing clinical trials to assess the efficacy of the BCG vaccine against Covid,” said Seyed Hasnain, a senior biologist, formerly with the National Institute of Immunology and now vice-chancellor at Jamia Hamdard, New Delhi.

“But it’s not surprising given what we know about BCG,” Hasnain told The Telegraph. We believe BCG works through a process called immune training,” Hasnain said. “Exposure to BCG trains the immune system to fend off attacks from other microbes.”

Several studies over the past two decades have suggested the century-old BCG vaccine not only protects children from severe TB, but also lowers the risk of sepsis in newborn and the risk of other respiratory infections in young children.

The ICMR-NIRT study is part of an ongoing nationwide six-city clinical trial in which 1,450 persons aged above 60 years will be administered the BCG vaccine to determine whether it is able to reduce mortality from Covid-19 infections.

In the coming weeks, doctors involved in the trial will measure differences in the incidence of the infection itself and severity of the infection among vaccinated volunteers and unvaccinated volunteers to determine if BCG will protect people from severe Covid-19.

In August this year, doctors in Germany, Greece, and the Netherlands had jointly published a study that had found that BCG was able to decrease the incidence of respiratory tract infections in elderly patients.

The doctors had presented their data collected between 2017 and 2019 and suggested that clinical trials should assess the efficacy of BCG vaccine to protect people from Covid-19.