The first full results from the interim analysis of the Oxford-AstraZeneca vaccine have shown that only three out of 24,000 participants had an adverse reaction to the vaccine. No cases of hospitalisation or death were reported among those who were given the vaccine. The results published in The Lancet, a well renowned medical journal, state that the vaccine is 27% effective in preventing asymptomatic transmission.
This data comes from the world's first peer-reviewed scientific publication of Phase 3 trial results of any COVID-19 vaccine.
AstraZeneca is currently seeking regulatory approval in many countries across the world. The company hopes that it will get the approval of MHRA, UK's regulator, within the next few weeks.
Mene Pangalos, executive VP, BioPharmaceuticals R&D at AstraZeneca, at a press briefing to coincide with the publication said, "We have rolling submissions with the MHRA and the EMA and we are working with the Serum Institute for their filings in India. The best way of sharing data is publishing in a high-quality peer-reviewed journal so that the media and scientific community can review it. We have published it so others can evaluate it, not to influence the regulator. We are the first group to have done that and it shows we have an effective vaccine which meets regulatory approval".
The published results state that there were no cases of hospitalisation or severe infection amongst the 23,745 people that had participated in the trial which were held in the UK, Brazil and South Africa. On the other hand, the group which was administered the control vaccine had 10 cases of hospitalisation for COVID-19 among which two were classified as severe, including one death.
There were 131 symptomatic COVID-19 cases in total amongst 11,636 participants in the UK and Brazil trials. Among these, 30.5 (0.5%) out of 5,807 cases were in the COViD-19 vaccine group and 101 (1.7%) out of 5,829 cases were in the control group, meaning that the vaccine has efficacy of around 70%
A group of 1,367 people in the UK was given a half dose which was followed by a full second dose "because of differences in the results of quantification methods between batches of the vaccine. The low-dose/standard-dose group did not include adults over the age of 55 years as the low dose was given in an early stage of the trial before recruitment of older adults had commenced," the paper states.
The results state that the vaccine efficacy is 62% when two full doses are administered. The efficiency increases to 90% when a half dose is given followed by a full dose. The results also show a vaccine efficacy against asymptomatic coronavirus transmission of 27%, this increases to 59% in the half dose, full dose regime.
"Our focus right now is on the data we have in hand from existing studies and we think that is sufficient," Pangalos added, explaining that the company has not decided whether to do a further study on the half dose, full dose, regimen. "I think even 62% effective is viable. We have shown no hospitalisations or deaths."
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