Once seen as the pioneer in the development of a vaccine against the coronavirus crisis, the British team was overtaken by the American pharmaceutical company Pfizer, whose injections, with a success rate of around 95%, were administered to retirees from the Kingdom. Kingdom on Tuesday in a world first. hailed as V-Day.
The detailed results of the AstraZeneca / Oxford trials have been eagerly awaited after some scientists criticized the lack of information in their initial announcement last month.
However, the Lancet study gave some additional clues as to why the efficacy was 62% for trial participants who received two full doses, but 90% for a smaller subgroup who received half and then a full dose.
“(This) will require more research as more data from the trial becomes available,” the study said.
Less than 6% of the trial participants in the UK received the lowest dose regimen and none of them were over 55 years old, which means that further research will be needed to investigate the efficacy of the vaccine in older people who are particularly susceptible to Covid-19.
Combining the results, the overall efficacy was 70.4%, Tuesday’s data showed. That’s above the 50% minimum set by the US Food and Drug Administration.
The Pfizer / BioNTech and Moderna Covid-19 vaccines have reported efficacy levels of more than 90% in late-stage trials.
But the AstraZeneca / Oxford vaccine is considered particularly important in addressing 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 around 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% or as high as 80%. The Pfizer / BioNTech and Moderna vaccines have efficiencies greater than 90% and are clearly more effective under test conditions.”
When asked whether 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.” .
AstraZeneca’s director of non-cancer research and development, Mene Pangalos, said he hoped that approval requests from regulators around the world could still be submitted this year.
“We hope that once the data is reviewed by the regulatory authorities, we can get approval at any time from the completion of the submission, which could be anytime from the end of this year to the beginning of 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 the full one, 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.
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The Oxford researchers said the vaccine was found to be safe, with three of the roughly 23,700 participants experiencing serious conditions that were possibly related to the Covid-19 vaccine or a standard meningitis vaccine given to a control group.
A case of a serious neurological disease, transverse myelitis, was reported 14 days after a booster injection of the Covid-19 vaccine, which “was possibly related to vaccination,” they said.
This case had resulted in a seven-week stay of trial in the United States and brief interruptions in trials in other countries.
In South Africa there was a case of fever above 40 ° C, but it was not revealed whether this participant received the vaccine because the person recovered quickly and continues the test without knowledge of the injection received, as is the norm.
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