The study, which involves 2,250 participants across four different countries, aims to build immunity against a variant of concern known as the Beta variant, which first emerged in South Africa. Researchers also said they’ll use the study to better understand COVID-19 and its associated issues.
“Testing booster doses of existing vaccines and new variant vaccines is important to ensure we are best prepared to stay ahead of the pandemic coronavirus, should their use be needed,” said Professor Sir Andrew J Pollard, chief investigator and director of the Oxford Vaccine Group, in a press release.
The dose will be administered as a booster to people who were previously fully vaccinated with either the original AstraZeneca vaccine or an mRNA jab — provided it’s been at least three months since their last shot.
The new vaccine will also be administered in a two-dose regimen in unvaccinated individuals, and as a second shot for those who have already received a dose of the original AstraZeneca jab.
Data from the trial is expected later this year, the press release said.
South Africa paused its use of the AstraZeneca COVID-19 vaccine after early results showed the jab was less effective against the Beta variant, which had become the dominant variant in the country. That variant has also been found in the U.K., where the AstraZeneca vaccine has served as a crown jewel in the vaccine rollout.
Britain had already entered into talks with AstraZeneca in early June to purchase doses of this new COVID-19 vaccine — once it’s been modified to better target the Beta variant, according to then-health minister Matt Hancock.
The press release announcing the human trials said Sunday that once the study is finished, the jab will be submitted to regulators as a “next-generation booster vaccine” using an expedited regulatory pathway.
Because the study will be administering the shot to those previously fully vaccinated using an mRNA vaccine, the research could also help scientists to further understand the effects of mixing mRNA vaccine doses with AstraZeneca, which is an adenovirus-based vaccine.
Early research from Europe has indicated that mixing doses of COVID-19 vaccines is safe and effective.
Preliminary results from a University of Oxford study published on May 12 found that mixing the Pfizer-BioNtech and AstraZeneca COVID-19 vaccines may increase the frequency of mild to moderate side effects. But these symptoms were short-lived — lasting no longer than a few days — and there were no hospitalizations or other safety concerns.
Meanwhile, a Spanish study released on May 18 showed that the presence of neutralizing antibodies rose sevenfold after people who already received a first shot of AstraZeneca vaccine were given the Pfizer dose, significantly more than the doubling effect observed after a second AstraZeneca shot.
A nationwide study was also launched in Canada last month to look at the safety and effectiveness of mixing and matching different types of shots.
In light of these emerging studies, Canada’s National Advisory Committee on Immunization (NACI) updated its guidance on June 1, recommending that approved COVID-19 vaccines can be safely mixed and matched in most scenarios.
“No data currently exist on the interchangeability of COVID-19 mRNA vaccines,” NACI wrote in its decision.
“However, there is no reason to believe that mRNA vaccine series completion with a different authorized mRNA vaccine product will result in any additional safety issues or deficiency in protection.”
NACI has stopped short, however, of recommending a second dose of AstraZeneca for those who received an mRNA vaccine as their first jab, citing safety concerns and limited data on the combination.
This new study could help researchers to glean an understanding of how the new AstraZeneca vaccine functions after a person has already been fully vaccinated with an mRNA vaccine – shining new light on an area of COVID-19 vaccine research that has yet to be explored.
— With files from Global News’ Saba Aziz
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