Researchers involved in ChAdOx1 nCoV-19 trials said the vaccine had shown evidence of founding the rhesus macaque monkeys immune system to ward off the deadly virus and showed no indications of side effects.
According to the study, which is yet to be peer-reviewed, a single vaccination dose was also effective in preventing lung damage – organs that can be severely affected by the virus.
“A single vaccination with ChAdOx1 nCoV-19 induced a humoral and cellular immune response in rhesus macaques,” the authors said.
“We observed a significantly reduced viral load in bronchoalveolar lavage fluid and airway tissue from vaccinated animals challenged with SARS-CoV-2 (Covid-19) compared to control animals, and no pneumonia was observed in vaccinated rhesus macaques,” they said.
The researchers found that after being exposed to high levels of the novel coronavirusnone of the six monkeys receiving the vaccine developed viral pneumonia. There was also no indication that the vaccine had made the animals more vulnerable.
The development has been welcomed as encouraging evidence of a vaccine currently undergoing human trials, but experts warn that it is not possible to see if it is as effective in humans.
“These results support the ongoing clinical trial of the vaccine in humans whose results are eagerly awaited,” Dr. Penny Ward, Visiting Professor of Pharmaceutical Medicine at King’s College London.
Sarah Gilbert, a professor of vaccinology at the University of Oxford’s Jenner Institute, who leads the research, has previously said she has a “high degree of confidence” in the vaccine.
“Of course, we have to test it and get data from people. We have to demonstrate that it actually works and stops people from getting infected with coronavirus before using the vaccine in the wider population,” she said.
UK drug giant AstraZeneca has concluded a “milestone partnership” with the Oxford University team, saying that 100 million doses could be made by the end of the year if the trials prove successful.
“We’re now starting to wait for a lawyer’s signal to see if people who have been vaccinated aren’t getting the disease, so that’s the next step,” said John Bell, a professor of medicine at the University of Oxford.
However, the team faces the risk that there may not be enough active disease in the community to allow participants to capture the natural metrics that continue to run as human trials progress in regions of the UK.
If the trial is successful in the UK, the Oxford team will turn to researchers at the Kenya Medical Research Institute (KEMRI) and approach the Government of Kenya for permission to evaluate in Kenya.
“We also want to make sure that the rest of the world is ready to manufacture this vaccine on a scale to reach populations in developing countries, for example, where the need is very high,” Bell said.
Meanwhile, it is hoped that results from the first human trials could be available next month after health workers in the frontline of the pandemic were among those in the first batch of trials in the UK.
England is the third best-hit country in the world with 234,441 coronavirus cases. The United States tops the table with 1,417,889 cases, followed by Russia at 252,245.
The deadly virus has so far claimed 33,693 lives in the UK.