AstraZeneca insists that its COVID-19 vaccine is highly effective, even after counting other illnesses in its study in the U.S., the most recent in an extraordinary public dispute with US officials.
In a late night press release on Wednesday, the drugmaker said it 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 that oversees the study accused AstraZeneca of choosing data selectively to publicize the protection offered by your vaccine. The panel, in a harsh letter to the company and U.S. health leaders, said the company had omitted some COVID-19 cases that occurred in the study, a move that could undermine confidence in science.
Some experts said the new data provided by AstraZeneca was “reassuring” and that the information was probably strong enough for US regulators to authorize the vaccine.
“AstraZeneca may have been too hasty to send the incomplete preliminary analysis, instead of waiting to analyze and send the complete data set,” said Julian Tang, a virologist at the University of Leicester who was not involved in the research. He said the updated details do not look substantially different from what was published earlier this week.
Data disputes during ongoing studies usually remain confidential, but at an unusual stage, the National Institutes of Health has publicly asked AstraZeneca to correct the discrepancy.
AstraZeneca relied on the findings of a predominantly American study of 32,000 people to help rebuild confidence in a vaccine that, despite being widely used in Britain, Europe and other countries, had a problematic launch. Previous studies have revealed inconsistent data on its effectiveness and, last week, a scare about blood clots caused some countries to temporarily suspend inoculations.
Most have restarted after the European Medicines Agency said the vaccine does not increase the overall incidence of blood clots, although it does not exclude a connection with some rare clots. On Thursday, Denmark announced that it would continue with the suspension of the vaccine, with officials saying they needed more information before making a decision.
The question now is whether the company’s latest calculations could ease tension in the United States. Even before the last fight, experts expressed concern that wrong steps in launching the vaccine could undermine confidence in the injection, which is crucial for global efforts to end the coronavirus pandemic, as it is cheap, easy to store and a cornerstone of the COVAX initiative that aims to bring vaccines to low and middle income countries.
Earlier on Wednesday, Dr. Anthony Fauci, the United States’ leading infectious disease specialist, told reporters that he hoped that when all the data were publicly examined by federal regulators, they would dispel any hesitation caused by the fight. He predicted that “it would end up being a good vaccine”.
AstraZeneca’s most recent calculations were based on 190 COVID-19 cases that occurred during the study, 49 more than it had included earlier in the week. The vaccine appears to be especially protective against the worst results, with no serious illness or hospitalizations among vaccinated study volunteers, compared with eight serious cases among those who received false injections, the company said. It did not provide an analysis of the rest of the cases.
Some European officials have questioned the degree of protection of the vaccine in older adults. In the US study, it was 85% effective on volunteers aged 65 and over, the company said. The study did not reveal security issues.
The updated information “confirms that our COVID-19 vaccine is highly effective in adults, including those aged 65 and over,” said AstraZeneca’s head of research, Mene Pangalos, in a statement. He said the company expects “the launch of millions of doses across America”.
The study has not ended, therefore, additional cases of COVID-19 may still occur. AstraZeneca warned that 14 possible additional cases are already being examined and that they could lead to further changes in the data.
The company plans to get the vaccine released by the Food and Drug Administration within a few weeks. The FDA will publicly discuss all evidence with its outside consultants before making a decision.
Stephen Evans, a vaccine specialist at the London School of Hygiene and Tropical Medicine, said it was difficult to understand why the dispute between AstraZeneca and US officials has spread to the public.
“Given the details provided here, it seems an unnecessary action to have raised concerns in public,” he said. “The results fluctuate as the data accumulates … what counts is the FDA’s assessment and this will be done based on scrutiny of all the data and not on press releases.” He said that any vaccine with an efficacy rate greater than 60% is useful.
He said it is unclear why there was “a breakdown in relations” between AstraZeneca and the independent American data experts who monitor the trial and fear that it could undermine confidence in the vaccine.
“This vaccine is very important for global health and disputes do not promote global health,” he said. “At least in the short term, it will undermine confidence both in the United States and in the rest of the world.”
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Associated Press medical writer Maria Cheng in London and Jan M. Olsen in Copenhagen contributed to this report.
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