Comparable endemic coronavirus nucleoprotein‐specific antibodies in mild and severe Covid‐19 patients

The severity of disease of Covid‐19 is highly variable, ranging from asymptomatic to critical respiratory disease and death. Potential cross‐reactive immune responses between SARS‐CoV‐2 and endemic coronavirus (eCoV) may hypothetically contribute to this variability. We herein studied if eCoV nucleoprotein (N)‐specific antibodies in the sera of patients with mild or severe Covid‐19 are associated with Covid‐19 severity. There were comparable levels of eCoV N‐specific antibodies early and during the first month of infection in Covid‐19 patients with mild and severe symptoms, and healthy SARS‐CoV‐2‐negative subjects. These results warrant further studies to investigate the potential role of eCoV‐specific antibodies in immunity to SARS‐CoV‐2 infection.