100-year-old tuberculosis vaccine may protect older people from COVID19: ICMR

A vaccine, used to treat tuberculosis for the past 100 years, could help prevent the risk of Covid-19 infections in older people, according to a study by the Indian Medical Research Council (ICMR).

Bacillus Calmette-Guérin (BCG) is considered one of the most widely used vaccines in the world, with around 130 million infants receiving this vaccine each year. There is increased interest in BCG vaccination of the elderly population, especially in countries with a high number of reported Covid-19 cases.

Previous studies have reported that BCG vaccination may confer protection against respiratory tract infections, involving viral infections.

The new study, published in the journal Science Advances, suggests that BCG could potentially act to inhibit biomarkers of inflammation by immune cells in the blood.

However, “this remains to be proven. Moreover, it is still unclear how long this inhibitory effect can persist,” said a team of researchers from the ICMR-National Institute for Tuberculosis Research and the ICMR-National Institute. of epidemiology. .

In addition, the study also reports that the recent BCG vaccination was not associated with hyperinflammation but was, in turn, associated with a downward modulated basal inflammatory state, which may play a protective role in the population. elderly against inflammatory diseases.

In addition, it is entirely possible that pathogen-specific immune responses may not be affected by the BCG vaccination or, on the contrary, actually improved, the researchers said.

In addition to a variety of pro-inflammatory cytokines, which could potentially play a detrimental role in Covid-19, anti-inflammatory responses including IL-10 and IL-33 – implicated in the severity of Covid-19 disease – have also been decreased in vaccinated individuals.

“In conclusion, the present study emphasizes that the effect of BCG vaccination is safe and does not lead to increased inflammation in the elderly. The results of this study not only corroborate the immunomodulatory properties of BCG vaccination, but also reveal a clear effect of (non) the specific immunogenicity of BCG vaccination on systemic inflammation, ”the researchers noted.

The study also recognized some limitations such as the lack of a placebo control group (only unvaccinated controls at baseline).

A better understanding of the results could support the efficacy of the vaccine and explore innovative applications of BCG vaccination, the team said.