Past infections with other coronaviruses influence COVID-19

Endemic coronaviruses have been causing human infections for many years, long before the recent emergence of SARS-CoV-2 which causes COVID-19. Jay Mizgerd and Manish Sagar (from the Section of Infectious Diseases) hypothesized that infections with endemic coronavirus, which are molecularly similar to SARS-CoV-2, might elicit cross-reactive immunity that influences what happens during a SARS-CoV-2 infection. They tested this hypothesis using medical records from the Boston Medical Center. They found that those who had been diagnosed within the prior 5 years with an endemic coronavirus infection fared better during COVID-19, compared to others who were similarly tested in the same time-frame but did not have endemic coronaviruses diagnosed. The rates of SARS-CoV-2 infection were similar between the groups, as were the rates of SARS-CoV-2 hospitalization. However, those with prior coronavirus diagnoses were less likely to need ICU admission and were less likely to die. These findings suggest that immunity against endemic coronaviruses may cross-react with SARS-CoV-2 and help
prevent serious infections in the lung. The study is published in the Journal of Clinical Investigation.