AstraZeneca and the University of Oxford on Sunday started fresh trials to test a modified vaccine against the more aggressive Beta variant of coronavirus, which first emerged in South Africa.
The trial of the “booster vaccine’ will involve around 2,250 participants from Britain, South Africa, Brazil and Poland, AstraZeneca said in a statement.
They include people who have been fully vaccinated with two doses of the original Oxford-AstraZeneca vaccine or an mRNA vaccine such as Pfizer as well as those who have not got the jab at all.
The new vaccine, known as AZD2816, has been designed using the same base as the main AstraZeneca shot but with minor genetic alterations to the spike protein based on the Beta variant.
Sir Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said: “It is important we continue to stay ahead of genetically distinct variants of the coronavirus. AZD2816 should help broaden the immune response of individuals against emerging variants of concern. Initiating the Phase II/III trial for AZD2816 means we can be prepared should a variant vaccine be required in the future.”
"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 Andrew Pollard, chief investigator and director of the Oxford Vaccine Group at the University of Oxford.
Britain has had a successful vaccine roll-out programme, but experts do not know how long protection lasts.
Initial data from the trial is expected later this year.
Current vaccines are believed to be less effective against the Beta variant, although it is the Delta variant that has now emerged as a major cause of concern.