On May 16, 2020, a single dose of ChAdOx1 nCoV-19, an investigational vaccine against SARS-CoV-2, has protected six rhesus macaques from pneumonia caused by the virus, according to NIH scientists and University of Oxford collaborators. SARS-CoV-2 is the virus that causes COVID-19. The researchers posted their data to the preprint server bioRxiv(link is external). The findings are not yet peer-reviewed but are being shared to assist the public health response to COVID-19. Based on these data, a Phase 1 trial of the candidate vaccine began Apr. 23 in healthy volunteers in the UK.