AstraZeneca COVID-19 vaccine shows promise in elderly, trial results expected by Christmas
Preliminary analysis of Phase 3 trial results will start after 53 infections
AstraZeneca and Oxford University's potential COVID-19 vaccine produced a strong immune response in older adults, data published on Thursday showed, with researchers expecting to release late-stage trial results by Christmas.
The data, reported in part last month but published in full in The Lancet medical journal on Thursday, suggests that those aged over 70, who are at higher risk of serious illness and death from COVID-19, could build robust immunity.
"The robust antibody and T-cell responses seen in older people in our study are encouraging," said Maheshi Ramasamy, a consultant and co-lead investigator at the Oxford Vaccine Group.
"We hope that this means our vaccine will help to protect some of the most vulnerable people in society, but further research will be needed before we can be sure."
Late-stage, or Phase III, trials are ongoing to confirm the findings, researchers said, and to test whether the vaccine protects against infection with SARS-CoV-2 in a broad range of people, including people with underlying health conditions.
Phase 3 interim analysis coming soon
Oxford University will start an initial analysis of data from its late-stage trial after 53 infections among its volunteers, the study's chief investigator said on Thursday.
The Oxford Vaccine Group's director, Andrew Pollard, said in a media briefing there were "lots of cases" of infections in its Phase III trial in Britain, Brazil and South Africa.
The first two sets of interim data from vaccine trials from Pfizer and BioNTech last week and Moderna on Monday were released after more than 90 infections among volunteers.
Pfizer had planned to publish initial data after about 60 infections, but it exceeded its target after the big jump in infections recently in the United States.
The Oxford-AstraZeneca COVID-19 vaccine candidate, called AZD1222 or ChAdOx1 nCoV-19, had been among the front-runners in global efforts to develop shots to protect against infection with the novel coronavirus, or SARS-CoV-2.
But rival drugmakers Pfizer Inc, BioNTech and Moderna Inc. have in the past 10 days edged ahead, releasing data from late-stage COVID-19 vaccine trials that shows more than 90 per cent efficacy.
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Unlike the Pfizer-BioNTech and Moderna shots, both of which use new technology known as messenger RNA (mRNA), AstraZeneca's is a viral vector vaccine made from a weakened version of a common cold virus found in chimpanzees.
The Phase II trial reported in The Lancet involved a total of 560 healthy volunteers, with 160 aged 18-55 years, 160 aged 56-69 years, and 240 aged 70 or over.
Volunteers got two doses of the vaccine or a placebo, and no serious side effects related to the AZD1222 vaccine were reported, the researchers said.
AstraZeneca has signed several supply and manufacturing deals with companies and governments around the world, including Canada.