AstraZeneca has been informed that it may have provided outdated data on the efficacy of its COVID-19 vaccine from a large-scale clinical trial in the U.S., the country’s National Institute of Allergy and Infectious Diseases (NIAID) said on Tuesday.
In an early morning statement, the NIAID said it had been informed by the national Data and Safety Monitoring Board (DSMB) late Monday that it was “concerned” about the information AstraZeneca provided.
“The DSMB expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data,” the NIAID said.
“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.”
On Monday, AstraZeneca announced that a large-scale Phase 3 study of 30,000 people in the U.S., Peru and Chile had shown its COVID-19 vaccine was 79 per cent effective in preventing symptomatic illness.
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It also said the two-dose regimen proved to have 100 per cent efficacy against hospitalization and death.
The trial results had been touted by NIAID director Dr. Anthony Fauci, the top infectious disease specialist, during a briefing on the coronavirus pandemic on Monday.
Global News has reached out to AstraZeneca for comment, but did not immediately hear back.
A request for comment from Health Canada has also not yet been returned.
The NIAID’s statement cast doubts over AstraZeneca’s plan to seek U.S. emergency use authorization for the vaccine in the coming weeks. The shot has already been approved for use in 70 other countries around the world, including Canada.
The concern over AstraZeneca’s data is also the latest public misstep for the company’s rollout of its vaccine, which has been plagued with confusion over data from past clinical trials along with recent reports linking the shot to blood clots in Europe.
Britain first authorized the vaccine based on partial results from testing in the United Kingdom, Brazil and South Africa that suggested the shot had about 70 per cent efficacy. But those results were clouded by a manufacturing mistake that led some participants to get just a half dose in their first shot — an error the researchers didn’t immediately acknowledge.
Then came more questions about how well the vaccine protected older adults and how long to wait before the second dose. Some European countries including Germany, France and Belgium initially withheld the shot from older adults and only reversed their decisions after new data suggested it is offering seniors protection.
The same U.S. clinical trial currently being scrutinized by the NIAID was suspended last fall for an unusual six weeks, as frustrated regulators sought information about some neurologic complaints reported in Britain. Ultimately, there was no evidence the vaccine was to blame and the trial continued.
Last week, more than a dozen countries, mostly in Europe, temporarily suspended their use of the AstraZeneca shot after reports it was linked to blood clots.
On Thursday, the European Medicines Agency concluded after an investigation that the vaccine did not raise the overall risk of blood clots, but could not rule out that it was connected to two very rare types of clots.
Health Canada also announced that day it had reached the same conclusion, concluding that the vaccine’s benefits “continue to outweigh the risks.”
–With files from the Associated Press
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