A COVID-19 vaccine could gradually be in the offing after a drug experimented on six rhesus macaque monkeys exposed to the virus showed significant result.
According to the new study — which has not been peer-reviewed or published in a scientific journal — the vaccine protected the monkeys that used it against the virus and is now undergoing human clinical trials.
The study also showed that the drug — ChAdOx1 nCoV-19 — had no side effects on the vaccinated animals while it also prevented damage to their lungs, which can be severely affected by the killer virus.
“We observed a significantly reduced viral load in bronchoalveolar lavage fluid and respiratory tract tissue of vaccinated animals challenged with SARS-CoV-2 compared with control animals, and no pneumonia was observed in vaccinated rhesus macaques,” the researchers said.
“Importantly, no evidence of immune-enhanced disease following viral challenge in vaccinated animals was observed. ChAdOx1 nCoV-19 is currently under investigation in a phase I clinical trial. Safety, immunogenicity and efficacy against symptomatic PCR-positive COVID-19 disease will now be assessed in randomised controlled human clinical trials.”
The study was carried out by researchers from the US government’s National Institutes of Health (NIH) and University of Oxford.
Experts have commended the study as encouraging signs for a vaccine currently undergoing human trials. They, however, warned that the vaccine cannot be considered as COVID-19 cure yet until it is as effective in humans.
Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, said the results were “very definitely” good news.
“The most important finding to me is the combination of considerable efficacy in terms of viral load and subsequent pneumonia, but no evidence of immune-enhanced disease,” he said.
“The latter has been a concern for vaccines in general, for example with vaccines against respiratory syncytial virus (RSV), and for SARS vaccines.
“This was a definite theoretical concern for a vaccine against SARS Cov-2 and finding no evidence for it in this study is very encouraging.”
On his part, Penny Ward, a visiting professor in pharmaceutical medicine at King’s College London, said the study was “helpful” given the fact that it had no side effects on the monkeys.
“These results support the ongoing clinical trial of the vaccine in humans, the results of which are eagerly awaited,” Ward said.