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LONDON — A U.S. health agency on Tuesday said that AstraZeneca may have included outdated information in trial results of its Covid-19 vaccine, potentially casting doubt over published efficacy rates.
It comes just one day after the findings of a large U.S. trial showed that the vaccine was safe and highly effective and throws into question whether AstraZeneca can seek U.S. clearance for the vaccine next month as planned.
The Data Safety Monitoring Board “expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data,” the U.S. National Institute of Allergy and Infectious Diseases said in a statement.
“We urge the company to work with the DSMB to review the efficacy data and ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”
The NIAID was notified of the concerns late Monday, along with AstraZeneca and the Biomedical Advanced Research and Development Authority. Led by White House Chief Medical Advisor Dr. Anthony Fauci, the NIAID is part of the National Institutes of Health.
On Monday, the U.S. trial results showed that the coronavirus vaccine developed by AstraZeneca and the University of Oxford is 79% effective in preventing symptomatic illness and 100% effective against severe disease and hospitalization.
The findings were welcomed as “surprisingly positive” and “good news for the global community.” It was thought the trial data could help to bolster public confidence in the shot and move it a step closer to U.S emergency use authorization.
AstraZeneca did not immediately respond to a CNBC request for comment.
Shares of AstraZeneca dipped 0.7% during Tuesday trading in London.
AstraZeneca said it planned to prepare for the primary analysis to be submitted to the U.S. Food and Drug Administration for emergency use authorization before mid-April.
Data from the late-stage human trial study was based on more than 32,000 volunteers across 88 trial centers in the U.S., Peru and Chile.
The Oxford-AstraZeneca vaccine had been temporarily suspended in several countries after reports of blood clots in some vaccinated people. Health experts sharply criticized the move, citing a lack of data, while analysts expressed concern about the impact on vaccine uptake as the virus continues to spread.
AstraZeneca said Monday that the independent DSMB had found no increased risk of blood clots.
Ruud Dobber, executive vice president of AstraZeneca’s biopharmaceuticals business unit, told CNBC’s “Squawk Box” on Monday that it was “very pleasing to see that even with a magnifying glass the Data Saftey Monitoring Board didn’t see any imbalance between the vaccinated group and the placebo group.”
“So, that gives us a lot of confidence,” he added.
Europe’s drug regulator said earlier this month that its initial investigation of possible side effects concluded the shot is safe and effective, adding the benefits still outweigh the risks.
The World Health Organization and the International Society on Thrombosis and Hemostasis have recommended that countries continue to use the Oxford-AstraZeneca vaccine.
Late last year, AstraZeneca faced criticism from U.S. health experts over the results and methods used in their phase 3 vaccine trials. Analysts at U.S.-based health care and biotech investment bank SVB Leerink said at the time that they believed the vaccine would “never be licensed in the U.S.”
AstraZeneca pushed back against the criticism, saying the studies “were conducted to the highest standards” and that more data would follow.