Specific Immunosuppression by SARS-CoV-2 ? Or Just making and getting more virus ?

The immunosuppression in individuals with severe COVID may be primarily due to the widespread distribution in patient tissues and organs. SARS-CoV-2 infects human CD4+ T helper cells, but not CD8+ T cells, and is present in T helper cells of blood and bronchoalveolar lavage of severe COVID-19 patients. A recent paper showed SARS-CoV-2 spike glycoprotein (S) directly binds to the CD4 molecule of helper T cells, which, in turn, mediates entry of SARS-CoV-2 into T helper cells but also requires ACE2 and TMPRSS2, Transmembrane Serine Protease 2 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359420/pdf/fon-2020-0571.pdf). Once inside T helper cells, SARS-CoV-2 replicates, impairs cell function, and causes cell death. SARS-CoV-2 infected T helper cells produce higher quantities of IL-10, which is associated with viral persistence and disease severity (medRxiv preprint doi: https://doi.org/10.1101/2020.09.25.20200329; posted September 28, 2020, which was not certified by peer review and https://www.cell.com/action/showPdf?pii=S2666-3791%2821%2900015-X. )

Besides immunosuppression, what will maintain the SARS-CoV-2 in populations? Researchers at Tulane University, Harvard University, MIT and Massachusetts General Hospital identified three factors that correlate to increased spread of COVID-19—obesity, age and date of infection. SARS-CoV-2 transmits through the air via large droplets exhaled when someone coughs or sneezes and small droplets people generate when they breathe. Using data from 194 healthy people and non-human primates with COVID-19, researchers determined low spreaders exhale less than 156 particles per liter of air and high spreaders exhale greater than 150 particles/L. There was no correlation with sex, but BMI-years did correlate (generated by multiplying age x BMI). Individuals with less than 650 BMI-years exhaled “significantly less aerosol” than those of 650 BMI-years or more. The elderly, the obese and the obese elderly are more likely to be superspreaders. Those younger than 26 and under 22 BMI are more likely to be low spreaders https://www.pnas.org/content/pnas/118/8/e2021830118.full.pdf.