Potential Protection of Pre-Existent Antibodies to Human Coronavirus 229E on COVID-19 Severity.

The causes of the broad spectrum of severity in COVID-19 are unknown. A protective effect through humoral immunity from previous infections by viruses of the SARS-CoV-2 family could explain a mild form of this disease. This study aimed to address whether the presence of antibodies against human seasonal coronaviruses (HCoVs) could prevent severe manifestations of COVID-19. A cross-sectional study was carried out in 165 participants. The presence of pre-existent antibodies against the seasonal HCoV-OC43, HCoV-HKU1, HCoV-229E, and HCoV-NL63 were detected. From all of the seasonal HCoVs studied, it was only found that being seropositive to HCoV-229E presented an association ( = 0.012) with developing mild clinical symptoms of COVID-19 or being asymptomatic. Multinomial regression analysis showed that being seropositive to HCoV-229E is associated with mild or moderate clinical symptoms for COVID-19. Statistical analysis also showed that being female is associated with being asymptomatic for SARS-CoV-2 infection or developing mild COVID-19. A subgroup analysis taking only seropositive to HCoV-229E revealed that females are more likely to develop asymptomatic SARS-CoV-2 infection (OR = 27.242, 95% CI 2.092-354.706, = 0.012). Our results suggest that previous infections by HCoV-229E could prevent more serious clinical manifestations of COVID-19, but these are not the only variables that influence this event.