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New results on a potential COVID-19 vaccine from drug maker AstraZeneca and the University of Oxford suggest that it is safe and about 70 percent effective, but questions remain about how well it can help protect people 55 and older. , a key concern for a vaccine officials around the world hope to trust because of its low cost, availability and ease of use.
Still, experts say the vaccine is likely to be approved, despite some confusion in the results and lower levels of protection than other vaccine candidates have shown.
Once seen as the pioneer in the development of a vaccine against the coronavirus crisis, the British team was surpassed by the American pharmaceutical company Pfizer, whose injections, with a success rate of around 95 percent, were administered to retirees of the UK on Tuesday in a world first. .
The Lancet medical journal on Tuesday published partial results of vaccine trials in the UK, Brazil and South Africa: safety results in 23,745 participants and protection levels in 11,636.
They are difficult to interpret because an error led some participants to receive a half dose followed by a full dose rather than two full doses as expected.
The researchers say the vaccine protected against the disease in 62 percent of those who received two full doses and in 90 percent of those who initially received half the dose. However, independent experts have said that the second group was too small (2,741 people) to judge the possible value of that approach and that more evidence is needed.
“[This] it will require more research as more data from the trial becomes available, ”the study said.
Less than 6 per cent of the trial participants in the UK received the lowest dose regimen and none of them were over 55 years old, meaning that more research will be needed to investigate the efficacy of the vaccine in people older than they are particularly susceptible to COVID-19.
Combining the results, the overall efficacy was 70.4 percent, peer-reviewed data showed Tuesday. That’s above the 50 percent minimum set by the US Food and Drug Administration.
Pfizer-BioNTech and Moderna’s COVID-19 vaccines have reported efficacy levels of more than 90 percent in late-stage trials.
But the AstraZeneca-Oxford vaccine is seen as particularly important in tackling the pandemic in the developing world, as it would be cheaper and easier to distribute.
“The basic message that the overall efficacy in all the trials reported here is about 70%, but with a clear description of its uncertainty,” said Stephen Evans, professor of pharmacoepidemiology at the School of Hygiene and Tropical Medicine at London.
“The statistical uncertainty is that the efficacy could be as low as 55 percent or as high as 80 percent. The Pfizer-BioNTech and Moderna vaccines have efficiencies greater than 90 percent and are clearly more effective under test conditions. “
When asked if the half-then full-dose regimen had been a mistake, Andrew Pollard, director of the Oxford Vaccine Group and lead investigator on the trials, told a news conference that it hadn’t been “planned.” .
Mene Pangalos, AstraZeneca’s head of non-oncology research and development, said he hoped that approval requests from regulators around the world could still be submitted this year.
“We hope that once the regulatory authorities review the data, we can get approval at any time from the completion of the submission, which could be anytime from the end of this year to early next,” he said.
However, Pollard admitted that the different results of the two dosing regimens complicated matters.
“Regulators will decide exactly what your label should say,” he said, when asked if regulators could approve the full two-shot regiment first, and then potentially the half-shot regiment, then full, when there is more data.
Pangalos also said he assumed that US regulators would want to see the results of an ongoing trial in the United States before giving approval.
The Oxford researchers said the vaccine was found to be safe, and that three of the approximately 23,700 participants experienced serious conditions that were possibly related to the COVID-19 vaccine or a standard meningitis vaccine given to a control group.
One case of a serious neurological disease, transverse myelitis, was reported 14 days after a booster shot of the COVID-19 vaccine, which “was possibly related to vaccination,” they said.
This case had led to a seven-week stay of trial in the United States and brief interruptions in trials in other countries.
There was one case of fever higher than 40 degrees Celsius (104 degrees Fahrenheit) in South Africa, but it was not revealed whether this participant received the vaccine because the person recovered quickly and continues the trial without knowledge of the injection received, as is the rule. .
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