LAUSR

Background Serologic testing provides better understanding of SARS-CoV-2 prevalence and its transmission. This study is the first investigation of the prevalence of antibodies to SARS-CoV-2 among blood donors in Saudi Arabia. Objective To estimate the seroprevalence of anti-SARS-CoV-2 antibodies among blood donors in Saudi Arabia during the early phase of the current pandemic. Methods Serology results and epidemiological data were analyzed for 837 adult blood donors, with no confirmed SARS-CoV-2 infection, in Saudi Arabia from 20 to 25 May 2020. Seroprevalence was determined using electrochemical immunoassay for detecting anti-SARS-CoV-2 antibodies. Results The overall seroprevalence of anti-SARS-CoV-2 antibodies was 1.4% (12/837). Non-citizens had higher prevalence compared to citizens (odds ratio 13.6, p = 0.001). Having a secondary education as the highest level of education was also significantly associated with high seroprevalence compared to higher education (odds ratio 6.8, p = 0.005). The data showed that the highest seroprevalence was in Makkah (8.1%), Madinah (4.1% with an OR of 0.48 (95% CI: 0.12-1.94), Jeddah (2.3%; OR 0.27; 95%CI: 0.31-2.25), and Qassim (2.9 %, OR: 0.34; 95%CI: 0.04-2.89) and these were not statistically different from the seroprevalence in Makkah region. Conclusions At the early stage of the pandemic in Saudi Arabia, the seroprevalence of antibodies to SARS-CoV-2 among blood donors was low but was higher among non-citizens These findings showed that non-citizens and the less educated may be less attentive to preventive measures. Monitoring seroprevalence trend over time require repeated sampling.