BCG vaccination induces enhanced frequencies of memory T and B cells and dendritic cell subsets in elderly individuals
Background: BCG vaccination is known to induce innate immune memory, which confers protection against heterologous infections. However, the effect of BCG vaccination on the conventional innate and adaptive immune cells subsets is not well characterized.
Methods: We investigated the impact of BCG vaccination on the frequencies of T cell, B cell, monocyte and dendritic 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 our clinical study to examine the effect of BCG on COVID-19.
Results: Our results demonstrate that BCG vaccination induced enhanced frequencies of central and effector memory CD4+ T cells and diminished frequencies of naive, transitional memory, stem cell memory CD4+ T cells and regulatory T cells. In addition, BCG vaccination induced enhanced frequencies of central, effector and terminal effector memory CD8+ T cells and diminished frequencies of naive, transitional memory and stem cell memory CD8+T cells. BCG vaccination also induced enhanced frequencies of immature, classical and activated memory B cells and plasma cells and diminished frequencies of naive and atypical memory B cells. While BCG vaccination did not induce significant alterations in monocytes subsets, it induced increased frequencies of myeloid and plasmacytoid DCs. Finally, BCG vaccination resulted in elevated levels of all antibody isotypes.
Conclusions: 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-Cov2 infection by enhancing heterologous immunity.
Will bacille Calmette-Guerin immunization arrest the COVID-19 pandemic?
Study to Evaluate the Effectiveness of BCG vaccine in Reducing Morbidity and Mortality in Elderly individuals in COVID-19 Hotspots in India
Indian Council of Medical Research has initiated a multi-centric study to find out if the Bacille Calmette Guerin (BCG) vaccine can reduce the morbidity and mortality of COVID-19 disease among elderly individuals aged 60 years and above residing in hotspots for COVID-19. The study is being carried out in 6 states of the country: Tamilnadu, Maharashtra, Gujarat, Madhya Pradesh, Rajasthan and Delhi in approximately 1500 healthy volunteers aged above 60 years. These participants will be followed up for a period of 6 months after vaccination. The study uses the conventional BCG vaccine that is used for vaccination of new born as a part of National Immunization programme of the country.
To evaluate efficacy of Bacillus Calmette-Guerin (BCG) in Reducing the Incidence and severity of COVID-19 in the high-risk population (BRIC): a phase III, Multicentric, Quadruple blind Randomized controlled trial
ICMR is sponsoring a phase III randomized multicentric study to evaluate efficacy of Bacillus Calmette-Guerin (BCG) in reducing the Incidence and severity of COVID-19 in the high-risk population (BRIC study). The study is being carried out in Delhi, Uttar Pradesh and West Bengal in 800 participants aged ≥18 to 60 years with underlying medical conditions such as Diabetes mellitus, Chronic kidney disease, Chronic heart conditions and Chronic lung disease.