AstraZeneca may have used outdated information in COVID-19 vaccine trial, US health officials say

Hours after COVID-19 vaccine collaborators AstraZeneca and Oxford University released data on their large clinical trial, federal officials said that information may have been missing a month’s worth of data.

The pair touted their vaccine trial results Monday in a news release and news conference, saying the two-dose shot would prevent 79% of symptomatic cases of COVID-19 and 100% of all severe cases and hospitalizations.

But a few minutes after midnight, the federal government took the unusual step of issuing its own news release saying the data may have been based on “outdated information.”

According to the statement, late on Monday, an independent review board that examined the AstraZeneca-Oxford data told the government and the company “that it was concerned by information released by AstraZeneca on initial data from its COVID-19 vaccine clinical trial.”

That independent group, called the Data Safety Monitoring Board or DSMB, “expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data. 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.”

Early Tuesday, Dr. Anthony Fauci, head of the government agency that released the information, said on Good Morning America the company released data available only through Feb. 17, while presenting it as if it were current information.

It’s unclear how much the up-to-date information may change the previously reported effectiveness rate.

“It really is unfortunate that this happened,” said Fauci, head of the National Institute of Allergy and Infectious Diseases, said. “This is very likely a very good vaccine.”

He said such missteps can contribute to hesitancy about vaccination. “It was not necessary,” he said. “If you look at it, the data really are quite good, but when they put it into the press release, the data wasn’t quite accurate.”

Medical staff prepares a syringe from a vial of the AstraZeneca coronavirus vaccine during preparations at the vaccine center in Ebersberg near Munich, Germany, Monday, March 22, 2021.

Fauci also complimented the monitoring board’s decision to go public when it saw the information AstraZeneca and Oxford had put out.

That body is one of many “safeguards” in place to ensure the public it is getting transparent, accurate information about vaccines, he said. “The DSMB picking up this discrepancy was an example of a safeguard.” Another, he said, is the Food and Drug Administration, which will review the data again, as will an independent advisory committee to the FDA.

For its part, AstraZeneca said Tuesday it had released a “pre-specified interim analysis with a data cut-off of 17 February.” In its previous news release, the company had referred to the data as “interim,” but did not explain that it was out of date.

“We have reviewed the preliminary assessment of the primary analysis and the results were consistent with the interim analysis. We are now completing the validation of the statistical analysis,” the company said in a statement, adding that it intend to issue results of that analysis within 48 hours.

Vaccine experts reacted to the news Tuesday with confusion and exasperation at a company that already has made several missteps during the vaccine development process.

“I just can’t quite understand the story, it’s so confusing,” said Dr. Peter Hotez, dean of the National School of Tropical Medicine at Baylor College of Medicine in Houston.

“I worry about the vaccine’s reputation and acceptance, especially in low and middle income countries,” he said via email. “We don’t have much to offer Africa and Latin America in terms of COVID-19 vaccines and this was supposed to be one of our workhorse vaccines in resource poor settings.”

The AstraZeneca-Oxford vaccine has been considered the least expensive COVID-19 vaccine and easiest to distribute across the world.

But its development and distribution have been riddled with problems, unlike the other COVID-19 vaccines, which have sailed through research trials and early production.

Most recently, the AstraZeneca-Oxford vaccine was put on hold in many European countries after reports that a small number of the 20 million people who received the shot developed a rare form of blood clot.

Last week, European drug regulators determined that the vaccine was safe and effective, but could not rule out that the vaccine contributed to these clots. Regulators are now monitoring vaccine recipients to see whether more clots occur.

The company also has had production issues, made a dosing error in a global trial and was forced to pause its trials last fall after a vaccine recipient suffered an unusual neurological condition.

The study released Monday included more than 30,000 participants from the U.S., Peru and Chile, showing strong protection against COVID-19 in all age groups and across health status, ethnicity and race. The study reported no severe safety issues, including no blood clots, and side effects comparable to other vaccines’.

Contact Karen Weintraub at

Health and patient safety coverage at USA TODAY is made possible in part by a grant from the Masimo Foundation for Ethics, Innovation and Competition in Healthcare. The Masimo Foundation does not provide editorial input.

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