"The vaccine was developed at the University of Oxford Jenner Institute. It uses a replication-deficient chimpanzee adenovirus to deliver a SARS-CoV-2 protein to induce a protective immune response. ChAdOx1 has been used to develop investigational vaccines against several pathogens, including a closely related coronavirus that causes Middle East respiratory syndrome (MERS)", the release said on Friday.
The scientists quickly adapted the adenovirus to the closely related coronavirus when the first cases of COVID-19 emerged. They showed that the vaccine rapidly induced immune responses against novel coronavirus in mice and rhesus macaques. The scientists then conducted vaccine efficacy testing on the macaques at NIH’s Institute for Allergy and Infectious Diseases laboratory in the state of Montana, where six monkeys received the vaccine 28 days before being infected with the coronavirus and three control animals that did not receive the vaccine, the release said.
"The vaccinated animals showed no signs of virus replication in the lungs, significantly lower levels of respiratory disease and no lung damage compared to control animals", the release said.
The findings are not yet peer-reviewed but are being shared to assist the public health response to COVID-19. Based on results on monkeys, a Phase 1 trial of the candidate vaccine began on 23 April in healthy volunteers in the United Kingdom, the release added. A Phase 1 trial determines if a new medicine is safe, followed by Phase 2 to determine whether the drug is effective.
Earlier on Friday, President Donald Trump announced what he called "Operation Warp Speed" to develop a COVID-19 vaccine as soon as possible, hopefully making inoculations available by the end of the year.