A single dose of Vaxzevria was shown to be 82 percent effective against cases of severe disease, hospitalization, or death caused by Beta/Gamma variant of SARS-CoV-2, according to pre-print data from the Canadian Immunization Research Network (CIRN).
Vaxzevria is another two-dose vaccine. However, follow-up time from the affiliated study was insufficient to gain data on two-dose efficacy as yet. Still, in addition to its favorable demonstration against the wide-spreading Beta/Gamma variant, the candidate also proved 87 and 90 percent effective at preventing hospitalization or death from the Delta and Alpha variants as well.
Delta, in particular, has been of serious concern to scientists for its increased resistance and virality.
“With different variants threatening to disrupt our route out of the pandemic, this real-world evidence shows that Vaxzevria, along with other vaccines used in Canada, provides a high level of protection against the most serious forms of the disease, even after just one shot,” Mene Pangalos, executive vice president, BioPharmaceuticals R&D, said. “It is essential that we continue to protect as many people as possible in all corners of the world in order to get ahead of this deadly virus.”
While capable of halting advanced cases of the diseases, Vaxzevria was less effective in preventing milder symptomatic cases. Against Beta/Gamma, it was only 50 percent effective; against Delta and Alpha, it was 70 percent and 72 percent effective, respectively. However, the vaccine was given on a two-dose regimen, and these figures represent results from first-dose data.
Still, a separate Phase 1/2 trial undertaken by the University of Oxford and University of the Witwatersrand in January likewise showed the vaccine to have limited efficacy against mild disease, primarily in the case of Beta.
The most recent study included 69,533 participants who tested positive for SARS-CoV-2 between December 2020 and May 2021 in Ontario, Canada. Of these, 40,828 tested positive for variants of concern.
Vaxzevria is currently operating under a conditional marketing authorization or emergency use in more than 80 countries, although it may be initially more recognizable by its former name, AZD1222.