WASHINGTON (NewsNation Now) — AstraZeneca says its COVID-19 vaccine was 76% effective in a new analysis of its U.S. trial, only slightly lower than the level in an earlier report this week criticized for using outdated data.
Just a day earlier, an independent panel that oversees the study had accused AstraZeneca of cherry-picking data to tout the protection offered by its vaccine. The panel, in a harsh letter to the company and to U.S. health leaders, said the company had left out some COVID-19 cases that occurred in the study, a move that could erode trust in the science.
Data disputes during ongoing studies usually remain confidential but in an unusual step, the National Institutes of Health publicly called on AstraZeneca to fix the discrepancy.
The small revision to the efficacy rate will go a long way to putting the vaccine back on track for gaining U.S. emergency use authorization – which it plans to seek in the coming weeks – and help AstraZeneca in its efforts to dispel doubts about its effectiveness and side-effects, independent experts said.
AstraZeneca also reiterated that the shot, developed with Oxford University, was 100% effective against severe or critical forms of the disease. There have been eight severe cases – all among trial participants who received the placebo.
Earlier Wednesday, Dr. Anthony Fauci, the top U.S. infectious disease expert, told reporters he hoped that when all the data was publicly vetted by federal regulators, it would dispel any hesitancy caused by the spat. He predicted it would “turn out to be a good vaccine.”
William Schaffner, an infectious disease expert from the Vanderbilt University School of Medicine, said he expects the shot to gain U.S. approval.
“The vaccine efficacy against severe disease, including death, puts the AZ vaccine in the same ballpark as the other vaccines,” he said.
The latest data was based on 190 infections among more than 32,400 participants in the United States, Chile and Peru. The earlier interim data was based on 141 infections through Feb. 17.
It also said the vaccine showed 85% efficacy in adults 65 years and older, higher than the 80% rate reported on Monday.
AstraZeneca said the latest data has been presented to the independent trial oversight committee, the Data Safety Monitoring Board, and it plans to submit the analysis for peer-reviewed publication in the coming weeks.
“The primary analysis is consistent with our previously released interim analysis, and confirms that our COVID-19 vaccine is highly effective in adults,” Mene Pangalos, executive vice president of BioPharmaceuticals R&D at AstraZeneca said in a statement.
The drugmaker noted there were 14 additional possible or probable cases to be analysed so numbers in later updates of the trial results may fluctuate slightly.
The updated 76% efficacy rate compares with rates of about 95% for vaccines from Pfizer/BioNTech and Moderna in their trial data.
Experts have noted, however, that AstraZeneca’s latest data is particularly significant because it was compiled after more infectious variants of the coronavirus became prevalent.
“This appears to be a very effective vaccine with no safety concerns,” said Paul Griffin, a professor at the University of Queensland.
“Hopefully, this should now give people the confidence that this vaccine is the right one to continue to use moving forward,” he said, adding that he and his parents have received the vaccine.
AstraZeneca’s vaccine is seen as crucial in tackling the spread of COVID-19 across the globe, not just due to limited supply of vaccines but also because it is easier and cheaper to transport than rival shots. It has been granted conditional marketing or emergency use authorisation in more than 70 countries.
The vaccine, once hailed as a milestone in the fight against the COVID-19 pandemic, has been dogged by questions since late last year when the drugmaker and Oxford University published data from an earlier trial with two different efficacy readings as a result of a dosing error.
Then this month, more than a dozen countries temporarily suspended giving out the vaccine after reports linked it to a rare blood clotting disorder in a very small number of people.
The European Union’s drug regulator said last week the vaccine was clearly safe, but Europeans remain sceptical about its safety.
Canada on Wednesday said it was safe but added a warning to the vaccine’s label about rare blood clots.
Its rollout has also been marred by production glitches and export curbs imposed by India and the European Union, threatening to slow global efforts to end the pandemic which has killed more than 2.8 million.
The Associated Press and Reuters contributed to this report. All reporting by AP’s Lauran Neergaard and Reuters’ Rocky Swift and Swati Pandey.