New findings on a possible COVID-19 vaccine from drugmaker AstraZeneca and the University of Oxford suggest it is around 70% safe and effective – but questions remain about how it can help protect them. people over 55, a key concern for an inoculation that officials around the world hope they can count on because of its low cost, availability and ease of use.
Still, experts say the vaccine appears likely to be approved, despite some confusion in the results and lower levels of protection than other vaccine candidates have shown.
Once considered to pioneer the development of a vaccine against the coronavirus crisis, the British team has been overtaken by the American drug maker Pfizer, whose injections – with a success rate of around 95% – were administered Tuesday to British retirees at a world premiere.
The Lancet medical journal on Tuesday published partial results of vaccine testing in the UK, Brazil and South Africa – safety results on 23,745 participants and protection levels on 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 intended.
Researchers say the vaccine protects against disease in 62% of people who received two full doses and in 90% of those who initially received the half dose. However, independent experts said the second group was too small – 2,741 people – to judge the possible value of this approach and that further testing was needed.
“[This] will require additional research as more data becomes available from the trial, ”the study said.
Less than 6% of UK trial participants received the lowest dosage regimen and none of them were over 55, meaning more research will be needed to study the efficacy of the vaccine in elderly people particularly susceptible to COVID-19.
Pooling the results together, the overall effectiveness was 70.4%, peer-reviewed data showed Tuesday. That’s above the 50 percent minimum set by the United States Food and Drug Administration.
Pfizer-BioNTech and Moderna’s COVID-19 vaccines have reported efficacy levels of over 90% in late stage trials.
But the AstraZeneca-Oxford vaccine is seen as particularly important for fighting the pandemic in developing countries because it would be cheaper and easier to distribute.
“The basic message that the overall efficacy of the trials reported here is around 70% but with a clear description of its uncertainty,” said Stephen Evans, professor of pharmacoepidemiology at the London School of Hygiene & Tropical Medicine.
“The statistical uncertainty is that the efficiency could be as low as 55 percent or as high as 80 percent. Both Pfizer-BioNTech and Moderna vaccines are above 90% effective and are clearly more effective under the conditions of the trials. “
Asked if the half-then-full-dose diet had been a mistake, Andrew Pollard, director of the Oxford Vaccine Group and chief trial investigator, told a press conference that he had been ” unexpected”.
Mene Pangalos, head of non-oncology research and development at AstraZeneca, said he hoped that applications for approval from regulators around the world could still be submitted this year.
“We hope that once the regulatory authorities have reviewed the data, we can obtain approval anytime from the completion of the submission, which could be any time from the end of this year to the start. next year, ”he said.
However, Pollard admitted that the different results from the two dosing regimens complicated matters.
“The regulators will decide exactly what their label should say,” he said, when asked if the regulators could approve the two-full-shot regiment first, then possibly the half-regiment, then full, when more data is available.
Pangalos also said he assumed U.S. regulators would want to see the results of an ongoing trial in the United States before giving their approval.
Oxford researchers said the vaccine was found to be safe, with three of the estimated 23,700 participants suffering from serious illnesses that may be related to the COVID-19 vaccine or a standard meningitis vaccine given to a control group.
A case of severe neurological disease, transverse myelitis, was reported 14 days after a booster shot of the COVID-19 vaccine, which was “likely related to vaccination,” they said.
The case had led to a seven-week trial stay in the United States and brief trial interruptions in other countries.
A case of fever above 40 degrees Celsius (104 degrees Fahrenheit) has occurred in South Africa, but it was not revealed whether this participant received the vaccine as the person recovered quickly and is continuing. testing without knowledge of the blow received, as is the norm. .