The Influence of Pre-Existing Immunity against Human Common Cold Coronaviruses on COVID-19 Susceptibility and Severity

The susceptibility to SARS-CoV-2 infection and the severity of COVID-19 manifestations vary significantly among individuals, prompting the need for a deeper understanding of the disease. Our objective in this study was to investigate whether previous infections with human common cold coronaviruses (hCCCoV) might impact susceptibility to and the progression of SARS-CoV-2 infections. We assessed the serum antibody levels against SARS-CoV-2 and four hCCCoV (H-CoV-OC43, -NL63, -HKU1, and -229E) in three distinct populations: 95 uninfected individuals (COVID-19-negative), 83 individuals with mild or asymptomatic COVID-19 (COVID-19-mild), and 45 patients who died due to COVID-19 (COVID-19-severe). The first two groups were matched in terms of their exposure to SARS-CoV-2. We did not observe any differences in the mean antibody levels between the COVID-19-mild and the COVID-19-negative participants. However, individuals in the COVID-19-mild group exhibited a higher frequency of antibody levels (sample/control) > 0.5 against H-CoV-HKU1, and >1 against H-CoV-229E and -OC43 (p < 0.05). In terms of severity, we noted significantly elevated H-CoV-NL63 IgG levels in the COVID-19-severe group compared to the other groups (p < 0.01). Our findings suggest a potential mild influence of hCCCoV antibody levels on the susceptibility to SARS-CoV-2 infection and the severity of COVID-19. These observations could aid in the development of strategies for predicting and mitigating the severity of COVID-19.