Page 71 - Covid 2021 June 2021

Protective roles of flu infections and BCG vaccination in lowering
COVID-19 mortality
The recent COVID-19 pandemic has caused a great loss of lives as well as affected economies in several countries. The loss of COVID-19 deaths is far greater in some countries compared to others. This observation led to perform epidemiological analysis using disease and vaccination data in the public domain with respect to measles, hepatitis B virus, polio, tuberculosis, and flu from twenty five countries across the globe. There is no correlation between COVID-19 incidences or deaths as well as vaccination coverage with respect to diseases such as measles, hepatitis B virus, and polio.
However, countries with lower cases of tuberculosis and higher cases of flu have a significant correlation with respect to COVID-19 deaths. In fact, countries with high BCG vaccination coverage show a significant negative correlation with COVID-19 deaths. Surprisingly, countries such as the USA, Italy, France and Spain which have flu vaccination, but not BCG vaccination, show maximum number of COVID-19 deaths. It appears that high numbers of flu infections are protective and can decrease the number of COVID-19 deaths. Importantly, countries with high flu cases and BCG vaccination, such as India, Egypt, South Africa etc., show relatively lower COVID-19 deaths, reinforcing the protective roles of BCG vaccination. Notably, these general trends are statistically significant for COVID-19 deaths but not COVID-19 incidences. The implications of results are discussed with respect to the roles of microbial infections in the respiratory tract, vaccinations, and other factors in lowering COVID-19 deaths.
Contact Info: nandi@iisc.ac.in
Website link:
https://covid19.iisc.ac.in/protective-roles-of-flu-infections-and-bcg-vaccination-in-lowering-covid-19-mortality- preprint-study/
Mechanistic modelling of the SARS-CoV-2 and immune system interplay unravels design principles for diverse clinico-pathological outcomes
The disease caused by SARS-CoV-2 is a global pandemic that threatens to bring long-term changes worldwide. Approximately 80% of the infected patients are asymptomatic or have mild symptoms such as fever or cough, while rest of the patients have varying degrees of severity of symptoms, with 3-4% mortality rate. Severe symptoms such as pneumonia and Acute Respiratory Distress Syndrome can be caused by tissue damage mostly due to aggravated and unresolved innate and adaptive immune response, often resulting from a cytokine storm. However, the mechanistic underpinnings of such responses remain elusive, with an incomplete understanding of how an intricate interplay among infected cells and cells of innate and adaptive immune system can lead to such diverse clinico-pathological outcomes.
A dynamical systems approach to dissect the emergent nonlinear intra-host dynamics among virally infected cells, the immune response to it, and the consequent immunopathology. By mechanistic analysis of cell-cell interactions, key parameters affecting the diverse clinical phenotypes associated with COVID-19 have been identified. This minimalistic yet rigorous model can explain the various phenotypes observed across the clinical spectrum of COVID-19, various co-morbidity risk factors such as age and obesity, and the effect of antiviral drugs on different phenotypes. It also reveals how a fine-tuned balance of infected cell killing and resolution of inflammation can lead to infection clearance, while disruptions can drive different severe
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