The AstraZeneca-OxfordUniversity vaccine (AZD1222) has shown that it is safe and effective at preventing symptomatic Covid-19 and that it protects against severe disease and hospitalisation, according to an interim analysis published in The Lancet.
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The peer-reviewed analysis for efficacy was based on 11,636 participants, with 131 symptomatic infections reported, from the late-stage Phase III UK and Brazil trials conducted by Oxford University, a note from AstraZeneca (AZ) said.
“As announced on November 23, 2020, the primary efficacy endpoint of the programme statistical plan, based on the pooling of two dosing regimens, showed that the vaccine is 70.4 per cent effective at preventing symptomatic Covid-19 occurring more than 14 days after receiving two doses of the vaccine. A secondary efficacy endpoint of prevention of severe disease demonstrated no cases of severe infections or hospitalisations in the vaccine group,” the note said.
A further analysis of the efficacy regimens showed that when the vaccine was given as two full doses, vaccine efficacy was 62.1 per cent and 90 per cent in participants who received a half dose followed by a full dose, the company said, on the dosing pattern that has received much critical attention from the scientific world.
Pascal Soriot, AZ Chief Executive Officer, said the peer-reviewed publication enables a full disclosure of the Oxford programme interim analysis. The results show that the vaccine is effective against Covid-19, with no severe infections and no hospitalisations in the vaccine group, as well as being safe and well tolerated. “We have begun submitting data to regulatory authorities around the world for early approval and our global supply chains are up and running, ready to quickly begin delivering hundreds of millions of doses on a global scale at no profit,” he said.
Submission of the data to regulatory authorities around the world has already begun, as part of their ongoing rolling reviews of the vaccine data for temporary use or conditional approval during this health crisis. The company is also seeking Emergency Use Listing from the World Health Organisation for an accelerated pathway to vaccine availability in low-income countries, he added.
The Serum Institute of India has a production and distribution alliance on the AZ-Oxford vaccine for India and other low and middle income countries. The analysis comes even as the India-arm of the trial had a volunteer allege serious adverse events, something that Serum Institute has clarified was not linked to the vaccine trial. Incidents had been reported earlier from the UK and Brazil arms of the trial as well.
The safety data published so far is from over 20,000 participants enrolled across four clinical trials in the UK (COV001 and COV002), Brazil (COV003) and, in addition, from South Africa (COV005), AZ said. The Lancet publication confirmed that AZD1222 was well tolerated and that there were no serious safety events confirmed related to the vaccine, it added.
The participants were from diverse racial and geographic groups who are healthy or have stable underlying medical conditions. This analysis provides safety data on 74,434 person-months of follow-up after the first dose and 29,097 person-months of follow-up after two doses, the note said, adding that the overall reported rates of serious adverse events were 0.7 per cent in the vaccine group and 0.8 per cent in the control group.
In addition to the Oxford-led programme, AstraZeneca is conducting a large study in the US and globally. In total, Oxford University and AstraZeneca expect to enrol more than 60,000 participants globally, the note said.
The company is also making progress in manufacturing with a capacity of up to 3 billion doses of the vaccine in 2021 on a rolling basis, pending regulatory approval. The vaccine can be stored, transported and handled at normal refrigerated conditions (2-8 degrees Celsius) for at least six months and administered within existing healthcare settings, it added.
AZD1222 was co-invented by the University of Oxford and its spin-out company, Vaccitech. It uses a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. After vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.