Halt of coronavirus trial is "safety valve" at work: Fauci

The top U.S. infectious disease expert said AstraZeneca’s suspension of final testing of its COVID-19 vaccine candidate shows “one of the safety valves” built into the studies to spot any potential problems.

“It’s unfortunate that it happened and hopefully they’ll be able to proceed along with the remainder of the trial. But you don’t know — they need to investigate it further,” Dr. Anthony Fauci, infectious diseases chief at the National Institutes of Health, told “CBS This Morning” on Wednesday.

Late Tuesday, AstraZeneca announced its final-stage studies are on temporary hold while the company investigates whether a research volunteer’s “potentially unexplained illness” is a side effect of the shot or a coincidence.

Behind-the-scenes monitors known as the “data and safety monitoring board” in Britain paused vaccinations while alerting its safety counterparts in the U.S., said Dr. Moncef Slaoui of Operation Warp Speed, the Trump administration’s vaccine development program.

Late last month, AstraZeneca began recruiting 30,000 people in the U.S. for its largest study of the vaccine. It also is testing the vaccine, developed by Oxford University, in thousands of people in Britain, and in smaller studies in Brazil and South Africa.

Scientists around the world have been scrambling to develop a vaccine against the coronavirus since the pandemic began. Nearly 900,000 deaths have been reported in the pandemic.

An AstraZeneca spokesperson confirmed the pause in vaccinations covers studies in the U.S. and other countries. The company would not provide further details of the illness.

Earlier stage studies of the vaccine hadn’t revealed any serious side effects.

“It’s important to point out that that’s the reason why you have various...