Colostrum from MERS-CoV seropositive camels for MERS prophylaxis and SARS-CoV-2 infection, a placebo controlled randomized trial

COVID-19 pandemic is currently relatively controlled, mainly due to effective vaccines. Preparedness for future outbreaks should include means for reducing transmission of SARS-CoV-2 and other coronaviruses like MERS-CoV. Approximately 72% of camels in Israel are seropositive for MERS-CoV and may exhibit cross-reactivity with serologically related SARS-CoV-2, suggesting therapeutic possibilities. Aims:To investigate the potential of camel-derived anti-MERS-CoV antibodies from camels colostrum for mucosal use in humans, as MERS-CoV prophylaxis and to control COVID-19 progression and infectivity. Methods:Using ELISA assay, we screened serum and colostrum of MERS-CoV seropositive camels for MERS-CoV antibody titers and neutralization potency and for cross-reactivity with SARS-CoV-2 spike. Next, we performed an open label placebo controlled randomized trial, comparing the effect of mucosal application of colostrum to placebo. Infectivity and viral load levels were evaluated daily up to 96 h. Results:Anti-MERS-CoV spike reactive antibodies with partial SARS-CoV-2 cross-reactivity were detected in 22 serum and 12 colostrum samples. While SARS-CoV-2 cross-neutralization was detected, its potency was significantly weaker than that of MERS-CoV. Neutralization of spike pseudotyped reporter viruses representing MERS-CoV reached ~ 1:500, while neutralization against SARS-CoV-2 wild type and variants was only at (NT50) ≤ 1:120. Forty-three COVID-19 patients were recruited to the randomized controlled trial. The primary endpoints did not differ between groups, with comparable decline in viral load (p = 0.311) and infectivity (p = 0.9641) after 24-h. Conclusions:In-vitro, camel colostrum-derived antibodies neutralize MERS-CoV, but a thin colostrum preparation did not reduce infectivity or viral load in SARS-CoV-2 infected individuals. The role of camel colostrum-derived antibody-concentrate and more viscous preparations merit further evaluation as potential prophylaxis and treatment against MERS-CoV.