Prior Coronavirus Infection May Affect COVID-19 Severity

Why the clinical manifestations of COVID-19 vary so markedly remains one of the most important unanswered questions in addressing this pandemic. Because four other endemic coronaviruses (eCoVs) cause human illness, one potential explanation is that recent infection with one of the eCoVs induces partial immunity to SARS-CoV-2, the virus that causes COVID-19, and thereby modulates the course of disease. This possibility has now been assessed by investigators at one academic medical center, who retrospectively identified patients with a comprehensive respiratory panel polymerase chain reaction (CRP-PCR) assay performed between May 2015 and March 2020. In the subpopulation that was then tested for SARS-CoV-2 infection between March and June 2020, the investigators compared COVID-19 severity in those with CRP-PCR results that were positive (eCOV+) or negative (eCoV−).

Of 15,928 patients with a CRP-PCR assay performed, those who were eCoV+ and eCOV− varied slightly in race and HIV status but not the proportion of individuals with one, two, or three comorbidities. The eCoV+ patients had a higher frequency of CRP-PCR and SARS-CoV-2 testing than the eCoV− patients. The two groups did not differ in the frequency of SARS-CoV-2 infection or hospitalization with COVID-19, but after adjustments for age, gender, body-mass index, and diabetes, the eCoV+ group had a significantly lower incidence of intensive care (odds ratio, 0.1; 95% confidence interval, 0.0–0.7) and a trend toward a lower probability of dying (OR, 0.3; 95% CI, 0.0–2.0).