Explained: How oxygen levels decline in Covid-19 patients Toronto– SARS-CoV-2, the virus causing Covid-19, infects immature red blood cells (RBC), reducing oxygen in the blood and impairing the immune response, say researchers. The study, published in the journal Stem Cell Reports, sheds light on why many Covid-19 patients, even those not in hospital, are suffering from hypoxia — a potentially dangerous condition in which there is decreased oxygenation in the body’s tissues. The study also shows why anti-inflammatory drug dexamethasone has been an effective treatment for those with the ...