Seroprevalence of human coronaviruses among patients visiting hospital-based sentinel sites in Uganda

Elijah Nicholas Mulabbi, Robert Tweyongyere, Fred Wabwire-Mangen, Edison Mworozi, Jeff Koehlerb, Hannah Kibuuka, Monica Millard, Bernard Erima, Titus Tugume, Ukuli Qouilazoni Aquino, Denis K. Byarugaba

Human coronaviruses are causative agents of respiratory infections with several subtypes being prevalent worldwide. They cause respiratory illnesses of varying severity and have been described to be continuously emerging but their prevalence is not well documented in Uganda. This study assessed the seroprevalence of antibodies against the previously known human coronaviruses prior 2019 in Uganda. A total 377 serum samples collected from volunteers that showed influenza like illness in five hospital-based sentinel sites and archived were analyzed using a commercial Qualitative Human Coronavirus Antibody IgG ELISA kit. Although there is no single kit available that can detect the presence of all the circulating coronaviruses, this kit uses a nucleoprotein, aa 340-390 to coat the wells and since there is significant homology among the various human coronavirus strains with regards to the coded for proteins, there is significant cross reactivity beyond HCoV HKU-39849 2003. This gives the kit a qualitative ability to detect the presence of human coronavirus antibodies in a sample. The overall seroprevalence for all the sites was 87.53% with no significant difference in the seroprevalence between the Hospital based sentinel sites (p = 0.8). Of the seropositive, the age group 1-5 years had the highest percentage (46.97), followed by 6-10 years (16.67) and then above 20 (16.36). An odds ratio of 1.6 (CI 0.863-2.97, p = 0.136) showed that those volunteers below 5 years of age were more likely to be seropositive compared to those above 5 years. The seropositivity was generally high throughout the year with highest being recorded in March and the lowest in February and December. The seroprevalence of Human coronaviruses is alarmingly high which calls for need to identify and characterize the circulating coronavirus strains so as to guide policy on the control strategies.