My colleagues and I often wonder why we see otherwise healthy 35- to 50-year-olds come into the hospital pretty sick with COVID-19. After all, isn’t it the 65 and older crowd with multiple chronic illnesses the ones that develop critical COVID-19? A recent study provides at least a partial explanation why some folks get much sicker than others.
First off, note that 30-40% of head colds are caused by coronaviruses. Most of us get one or two colds a year. SARS-CoV-2 is the particular coronavirus that causes COVID-19. Another human coronavirus, called OC43, commonly causes infection, which leads to antibody production. It turns out that these antibodies help protect us from severe disease caused by the COVID-19 coronavirus. Some of these otherwise healthy but now critically ill middle-aged COVID-19 patients just don’t have antibodies to OC 43. So SARS-CoV-2 spreads through them more virulently.
Steve Parker, M.D.