In response, AstraZeneca said that it is working on more up-to-date information and that the more recent findings are consistent with its initial announcement that the vaccine offered strong protection. It promised an update within 48 hours.
In an extraordinary rebuke, just hours after AstraZeneca on Monday announced its vaccine worked well in the U.S. study, an independent panel that oversees the study scolded the company for cherry-picking data, according to a senior administration official.
The letter goes on to say, “Decisions like this are what erode public trust in the scientific process.”
The U.S. study was supposed to help settle lingering questions about the effectiveness of a vaccine that is being widely used in Europe and other parts of the world and is about to be considered for use in Americans, too.
Rebuilding confidence in its vaccine was what AstraZeneca had hoped to accomplish on Monday, when it announced that a predominantly U.S. study of 32,000 volunteers showed its vaccine was 79% effective in preventing symptomatic COVID-19 disease, and that no vaccinated volunteers had suffered severe illnesses or hospitalizations.
But shortly after midnight, the National Institutes of Health issued a statement saying the independent monitors that oversee the study had “expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data.”
The NIH urged the company to “ensure the most accurate, up-to-date efficacy data be made public as quickly as possible.”
Outside experts were surprised and puzzled by the spat. But they noted that ultimately the Food and Drug Administration will scrutinize all the data before deciding whether AstraZeneca's vaccine can be rolled out in the U.S.
“It would seem that whatever this communication misstep is, at the end of the day the data will have to stand for itself,” said Dr. Jesse Goodman of Georgetown University, a former FDA vaccine chief.
The NIH's Dr. Anthony Fauci told ABC's “Good Morning America” that the incident “really is what you call an unforced error" and that he expects the discrepancy to be straightened out.
Fauci also said the episode shows the U.S. regulatory system is working: “The data and safety monitoring board picking up this discrepancy was an example of a safeguard.”
Every vaccine trial is overseen by a “data and safety monitoring board,” or DSMB. These boards include scientists and statisticians who are experts in their fields but have no ties to either the government or the vaccine makers.
The DSMB watches for safety concerns and also deems when the study has met pre-determined endpoints showing it's time for an effectiveness calculation. It was the NIH-appointed DSMB that raised the concerns about AstraZeneca's data, in a letter first reported by The Washington Post and the New York Times.
On Tuesday, AstraZeneca said that the data it first released included COVID-19 cases that occurred up to Feb. 17, as the study rules specified, and that it is continuing to analyze cases that have occurred since then. It said a preliminary analysis of more recent data was consistent with what it had already reported.
It is common for companies developing COVID-19 vaccines to release early data and to continue studying results as they come in.
The vaccine is used widely in Britain, across the European continent and in other countries, but its rollout was troubled by inconsistent study reports about its effectiveness, and then last week a scare about blood clots that had some countries temporarily pausing inoculations.
The U.S. study findings announced by AstraZeneca were consistent with studies from elsewhere — and real-world use in Britain — that found the vaccine offers good protection against the worst COVID-19 has to offer. But company executives refused repeated requests from reporters to provide a breakdown of the 141 COVID-19 cases it was using to make the case for the shot's effectiveness.
The company has said it aims to file an application with the FDA in the coming weeks.
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