As the race to find a vaccine for COVID-19 continues, researchers from the University of Oxford published a preliminary report earlier this week (20 July 2020) in The Lancet showing promising results from Phase 1/2 trials of its vaccine candidate, known as ChAdOx1 nCov-19.
ChAdOx1 nCov-19 is one of two vaccine candidates that Australia’s national science agency, CSIRO, has been evaluating through a pre-clinical trial and their experts weigh in on the latest developed with Oxford’s candidate and share their insights on CSIRO’s pre-clinical trials.
‘Encouraging results but safety of highest importance’
“Preliminary findings from the Phase ½ trials of the University of Oxford’s vaccine candidate show encouraging results,” says CSIRO’s Health and Biosecurity Director, Dr Rob Grenfell.
“The report shows the vaccine candidate generated an immune response, making antibodies and stimulating T-cells to fight COVID-19.”
Dr Grenfell adds that while the race to find a vaccine is moving at rapid speed due to the urgent global need for a vaccine, “we can never forget safety is still of the highest importance”.
“While these are hopeful results, there’s still a long way to go before we have a viable vaccine at our fingertips.
“We need to await the additional Phase 3 clinical trials, that will study the potential vaccine candidate’s performance and safety … It won’t be clear if the vaccine candidate works, and is safe for the broader population, until these large-scale clinical trials are completed, and we can see through the randomised approach that the vaccinated group is protected,” he cautions.
How to administer the potential vaccine?
Another issue to consider in the development of a vaccine, as Dr Grenfell points out, is determining the best way to administer the vaccine.
“As part of CSIRO’s preclinical study of Oxford’s vaccine candidate, our scientists evaluated the efficacy of one versus two doses, as well as administration of the vaccine via a nasal delivery and/or an intramuscular injection,” says Dr Grenfell.
Director of CSIRO’s Australian Centre for Disease Preparedness (ACDP), Dr Trevor Drew explains that the “CSIRO recently completed pre-clinical trials for two vaccine candidates, including Oxford’s ChAdOx1 nCoV-19 at ACDP”, which started in March “involved obtaining and characterising SARS-CoV-2 – the causative virus of COVID-19 – and establishing a ferret model in which to test vaccines”.
“A cohort of ferrets were vaccinated and, following a number of weeks to allow their immunity to develop, challenged with the virus,” says Dr Drew.
“Researchers then assess the efficacy of the vaccine candidates by characterising the immune response of the animals to the vaccines and comparing the level of protection between vaccinated and unvaccinated ferrets, as well as the different delivery methods and single versus double doses.”
Dr Drew says that the “early data from these trials has been shared with the University of Oxford”.
The results are currently going through review, quality assurance and a compliance audit. Once this is complete the results are expected to be published.
