AstraZeneca emphasizes that its COVID-19 vaccine is highly effective, even after counting additional illnesses in its US study, the latest in an extraordinary public dispute with US officials.
In a press release on Wednesday evening, the drugmaker said it had analyzed more data from that study and concluded that the vaccine is 76% effective in preventing symptomatic COVID-19, instead of the 79% reported earlier in the week.
Just a day earlier, an independent panel overseeing the investigation had accused AstraZeneca of data collection to promote the protection offered by the vaccine. The panel said in a hard letter to the company and to US health leaders that the company had omitted some of the COVID-19 cases that appeared in the investigation, a move that could erode confidence in the science.
Some experts said the new data from AstraZeneca was “reassuring” and that the information was likely solid enough for US regulators to approve the vaccine.
“AstraZeneca may have been just too hasty to submit the earlier incomplete interim analysis rather than wait to analyze and submit the full dataset,” said Julian Tang, a virologist at the University of Leicester who was not involved in the study. used to be. He said the updated details did not look materially different from what was published earlier this week.
Data disputes during ongoing investigations typically remain confidential, but in an unusual move, the National Institutes of Health publicly called for AstraZeneca to resolve the discrepancy.
AstraZeneca relied on the findings of a primarily US study of 32,000 people to help restore confidence in a vaccine that, despite being widely used in Britain, Europe and other countries, has had a difficult rollout. Previous studies have provided inconsistent data on its effectiveness, and last week, a fear of blood clots caused some countries to temporarily halt vaccinations.
Most have since been restarted after the European Medicines Agency said the vaccine does not increase the overall incidence of blood clots, although it did not rule out an association with some rare clots. On Thursday, Denmark announced that it would continue to suspend the vaccine, with officials saying they needed more information before making a decision.
The question now is whether the company’s latest calculations can put an end to tension in the United States. Even before the latest feud, experts had expressed concern that missteps in vaccine rollout could undermine confidence in the shot, which is critical to the global effort to end the coronavirus pandemic as it is cheap, easy to store and a pillar of the COVAX initiative to bring vaccines to low and middle income countries.
Earlier Wednesday, Dr. Anthony Fauci, America’s top infectious disease expert, told reporters that he hoped that having all the data publicly vetted by federal regulators would alleviate any hesitation caused by the feud. He predicted it would “turn out to be a good vaccine.”
AstraZeneca’s latest calculations were based on 190 COVID-19 cases that occurred during the study, 49 more than earlier in the week. The vaccine appears to be especially protective against the worst of outcomes, with no serious illness or hospitalization among vaccinated volunteers, compared to eight serious cases in those who received sham injections, the company said. It did not provide a breakdown of the rest of the cases.
Some European authorities have questioned how protective the vaccine is in older adults. In the US study, it was 85% effective in volunteers age 65 and older, the company said. The study did not raise any safety concerns.
The updated information “confirms that our COVID-19 vaccine is highly effective in adults, including those aged 65 and over,” said AstraZeneca principal investigator Mene Pangalos. He said the company is looking forward to “rolling out millions of doses across America.”
The investigation is not over yet, so more COVID-19 cases could arise. AstraZeneca warned that an additional 14 possible cases are already being investigated and that this could lead to further changes in the data.
The company plans to seek approval of the vaccine by the Food and Drug Administration within weeks. The FDA will publicly discuss all evidence with its outside advisers before making a decision.
Stephen Evans, a vaccine expert at the London School of Hygiene and Tropical Medicine, said it was difficult to understand why the dispute between AstraZeneca and US officials came out in the open.
“Given the details given here, it seems an unnecessary action to have publicly raised concerns,” he said. “Results fluctuate as data accumulates … what counts will be the FDA review and it will be based on full data review and not press releases.” He said any vaccine with an efficacy rate greater than 60% is helpful.
He said it was unclear why there was “a break in relations” between AstraZeneca and the independent US data experts who followed the trial, and was concerned that this could undermine confidence in the vaccine.
“This vaccine is so important to global health, and the disputes are not conducive to global health,” he said. “At least in the short term, (this) will undermine confidence in the US and, more importantly, in the rest of the world.”
Medical writer Maria Cheng of the Associated Press in London and Jan M. Olsen in Copenhagen contributed to this report.
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