US health agency raises 'concern' over AstraZeneca COVID vaccine trial data

AstraZeneca may have used "outdated information" in the results of a large-scale COVID-19 vaccine trial, a US health agency said on Tuesday, casting fresh doubt on the shot, its potential US rollout and plunging its developers, once again, into controversy.

According to reports, the highly unusual rebuke from federal health officials comes just one day after interim data from the medicine manufacturer showed better-than-expected results from the US trial which had been seen as a scientific counter to concerns that have dogged the shot since late last year.

The vaccine developed with partner Oxford University was 79% effective in preventing symptomatic illness in the large trial that also took place in Chile and Peru, according to the data.

It was also 100% effective against severe or critical forms of the disease and hospitalisation, and posed no increased risk of blood clots.

The Data Safety Monitoring Board (DSMB), an independent committee overseeing the trial, has "expressed concern that AstraZeneca may have included outdated information from that trial, which may have provided an incomplete view of the efficacy data," the US National Institute of Allergy and Infectious Diseases (NIAID) said in a statement released after midnight in the United States.

"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," it said, adding that the DSMB had informed AstraZeneca of its concerns.

AstraZeneca did not immediately respond to a Reuters request for comment. Its shares were down 1% in early morning trade.

Doubts raised

Although hailed as a milestone in the fight against the COVID-19 pandemic when it emerged as a vaccine contender last year, the AstraZeneca shot has seen a steady stream of questions raised about its efficacy, dosing regimen and possible side effects.

More than a dozen European countries halted use of the vaccine earlier this month after reports linked it to a rare blood clotting disorder in a very small number of people.

Germany and France resumed inoculations after the EU's drug regulator said last week it was safe but an opinion poll on Monday showed Europeans remained skeptical about its safety.

Before the blood clot concerns, there were also earlier separate late-stage studies, run by partner Oxford University, that had raised questions about its dosing regimen and the lack of data about its efficacy for elderly people.

The latest data, which has yet to be reviewed by independent researchers, was based on 141 infections among 32,449 participants.

SS