Less severe course of COVID-19 is associated with elevated levels of antibodies against seasonal human coronaviruses OC43 and HKU1 (HCoV OC43, HCoV HKU1)

"Abstract: We performed a biomarker study to assess the impact of prior infections with seasonal coronaviruses on COVID-19 severity. Sixty patients with confirmed COVID-19 infections were included (age 30–82; 52 males, 8 females): 19 inpatients with critical disease, 16 inpatients with severe or moderate disease, and 25 outpatients...

Discussion: ... This biomarker study assessed a potential relationship between prior infections with seasonal coronaviruses–measured as antibody levels–and the severity of COVID-19 disease. It was shown that elevated antibody levels for HCoVs OC43 and HKU1 were associated with less need for intensive care therapy. A trend towards a reduced length of hospital stay was also observed. Our findings are concordant with a recent study based on data from electronic medical records (Sagar et al., 2020)."