An old person walks out after receiving his COVID-19 jab in New Delhi.

(Piyal Bhattacharjee/BCCL Delhi)

COVID-19 vaccines appear to be doing their job spectacularly well so far. Among those that have received both doses of vaccines, the chances of severe infections, hospitalisations and coronavirus-induced deaths have fallen drastically all around the world.

However, the distribution of these vaccines has remained extremely unequal. While more than 4 billion vaccine doses have been administered globally so far, more than 80% of those have gone to high- and upper-middle-income countries, which account for less than half of the world’s population.

Furthermore, the fact that some rich countries have already begun administering the third, booster dose of vaccines while a major chunk of the population from the poorer countries still waits for its first dose, only underlines the skewed nature of vaccine accessibility.

While fixing this unequal distribution and focusing on meeting the global vaccine targets would be the ideal solution to this problem, a temporary half-solution in the meantime would be to find another effective way to reduce COVID-19 mortality.

Speaking of, scientists may well have stumbled upon one such way; and while it is based on vaccination, the vaccine in question was manufactured a century before COVID-19 crossed paths with humanity.

A team of researchers from the CMR-National Institute for Research in Tuberculosis and the ICMR-National Institute of Epidemiology, both based in India, has found that an old vaccine used to reduce the threat of tuberculosis may provide older people with some protection against COVID-19.

The vaccine in question is the Bacillus Calmette-Guérin (BCG) vaccine, which has been used to prevent tuberculosis since 1921 and is also the most widely used vaccine worldwide.

The researchers re-looked at this vaccine to see if it might prove useful for unvaccinated older people. They administered the BCG vaccine to 82 volunteers aged between 60 and 80, and a month later, collected and studied their blood samples.

Analysis of the samples revealed that among these vaccinated individuals, there was a significant decrease in several cytokines (small proteins that control immune system cell activity) like IL-6, type 1 interferons, interleukin-2 (IL-2) and TNF-alpha GM-CSF.

These cytokines have been associated with promoting inflammation. In fact, this low-grade, chronic inflammation in question tends to develop as people get older, and it makes them susceptible to many types of diseases. It also plays a role in intensifying COVID-19 symptoms, which partly explains why older people are far more likely to succumb to coronavirus infections.

Researchers found that the levels of the same cytokines were lower in vaccinated people as compared to those in a control group of unvaccinated volunteers. The BCG-vaccinated volunteers also had lower levels of some chemokines (a family of chemoattractant cytokines) such as matrix metalloproteinases and phase proteins, both of which have also been associated with promoting inflammation.

As these cytokines function as drivers of more severe COVID-19, the BCG vaccine’s ability to kill them makes it a powerful stop-gap measure for older people awaiting vaccination—especially in countries with low vaccine availability.

It could reduce inflammation in older people if they do get infected while waiting for their COVID-19 shot, effectively saving their lives and reducing the overall COVID-19 mortality.

The findings of this study were recently published in the journal Science Advances, and can be accessed here.


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