Bacillus Calmette-Guerin (BCG) vaccine that primarily provides protection against tuberculosis (TB) is also beneficial against coronavirus disease (Covid-19) among elderly, scientists at the Indian Council of Medical Research (ICMR) have found, and results have been published in a pre-print study.
ICMR scientists have been investigating the impact of BCG vaccination on the frequencies of immunity cells–T cell, B cell, monocyte (white blood cells), and dendritic (antigen presenting) cell subsets as well as total antibody levels in a group of healthy elderly individuals (age 60-80 years) at one month post vaccination as part of their clinical study to examine the effect of BCG on Covid-19.
Elderly people, above 60 years of age, and those with comorbidities such as diabetes, hypertension, cardiac and kidney diseases etc. are high risk groups that tend to develop sever form of illness, and also have a high mortality rate among Covid-19 positive cases.
“BCG vaccination was associated with enhanced innate and adaptive memory cell subsets, as well as total antibody levels in elderly individuals, suggesting its potential utility in SARS-Cov-2 infection by enhancing heterologous immunity,” scientists concluded in the research.
BCG vaccine is administered to newborn babies as a part of Centre’s National Immunization Programme for more than 50 years in the country.
ICMR in a statement said, “In an ongoing study, scientists at ICMR have found that the BCG vaccine induces increased memory cell responses and total antibody production in elderly.”
From July 2020 through September 2020, 86 individuals were enrolled in the study with 54 in the vaccinated arm and 32 in the unvaccinated arm. All the vaccinated individuals were followed up at month 1 post vaccination with no loss to follow-up. Median age was 65 (Range: 60-78) years in BCG vaccinated group and 63 years (Range: 60-80) in the unvaccinated group.
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Several clinical trials are currently underway to examine the effect of BCG. ICMR scientists picked up investigation in elderly population because most of those are evaluating its role in protecting health care workers and other individuals from SARS-CoV-2 infection or disease; and very few studies are examining the protective effect of BCG vaccination against SARS-CoV-2 in the elderly population group.
Previous studies in elderly individuals have shown that BCG vaccination protected against respiratory infections in Indonesia, Japan, and Europe.
“These data fit very well with the recent finding that BCG vaccination in elderly patients was associated with increased time to first infection and protection against viral respiratory pathogens,” the paper says.