AstraZeneca says its COVID-19 vaccine is strongly effective, after recalculating data from its late-state U.S. clinical trial, which federal health officials said was incomplete.
In a press release sent out late Wednesday, the British drugmaker said the vaccine is 76% effective in preventing symptomatic COVID-19. This is slightly lower than the 79% that the company stated on Monday.
The effectiveness at preventing serious illness and hospitalization remained at 100%. The company also raised the efficacy at protecting people who are 65 and above to 85% compared to 80% from earlier in the week.
The Data and Safety Monitoring Board, an independent panel of experts that oversees clinical trials, had accused AstraZeneca of cherry-picking data to tout the protection offered by its vaccine.
Data disputes during ongoing studies typically remain confidential but in an unusual step, the National Institutes of Health released a statement saying AstraZeneca "may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data," and publicly called on the drugmaker to fix the discrepancy.
One of the key changes that AstraZeneca released was that there were 190 symptomatic cases of COVID-19 in its trial. That is 49 more than the company initially announced. There were 32,449 participants and around 20,000 of them were given the vaccine.
The change in efficacy may be minimal, but the overall impact on people’s trust of the science is worrisome to health officials.
"We are always concerned when there is an apparent miscommunication — if you want to use that word — that that would add to an already existing level of vaccine hesitancy," White House Chief Medical Advisor Dr. Anthony Fauci, said on Wednesday before the revised information was released.
Fauci also tried to sound a note of reassurance, adding, "this is gonna turn out to be a good vaccine."
AstraZeneca had been counting on findings from the study to help rebuild confidence in a vaccine that, despite being widely used in Europe, Britain and other countries, has had a troubled rollout.
Previous studies have turned up inconsistent data about its effectiveness. And last week, concerns about an increased risk of blood clots led several countries to pause distribution. European regulators then reviewed the vaccine, dismissed the risk, and gave the all-clear. AstraZeneca also said there was no elevated risk of blood clots found in the U.S. trials.
AstraZeneca officials say they will be applying for emergency use authorization from the FDA, which will then do a formal analysis of the data.
"At the end of the day everything is gonna be open and transparent and hopefully that will dispel any hesitancy that was associated with this little bump in the road," Fauci said.
Stephen Evans, a vaccines expert at the London School of Hygiene and Tropical Medicine, said it was difficult to understand why the dispute between AstraZeneca and U.S. officials spilled into the public.
“Given the details given here, it seems an unnecessary action to have raised concerns in public,” he said. “Results fluctuate as data accumulate ... what counts will be the FDA assessment and that will be done based on scrutiny of the full data and not press releases.” He said any vaccine with an efficacy rate higher than 60% is useful.
He said it was unclear why there was “a breakdown in relations” between AstraZeneca and the independent U.S. data experts monitoring the trial and worried that could undermine confidence in the vaccine.
“This vaccine is so important for global health, and the disputes do not promote global health,” he said. “At least in the short term, (this) will undermine confidence both in the U.S. and more importantly in the rest of the world.”
LISTEN NOW on the RADIO.COM App
Follow RADIO.COM
Facebook | Twitter | Instagram