FDA Clears AstraZeneca COVID-19 Vaccine to Resume US Trial

US studies for coronavirus 2019 (COVID-19) vaccine candidate AZD1222 from AstraZeneca and the University of Oxford have been permitted to resume following sign-off from the US Food and Drug Administration (FDA), which launched an independent investigation into 2 adverse neurological events in trial participants earlier this month.

According to The Wall Street Journal, the FDA investigation has concluded as of Friday afternoon, with investigators observing no evidence the adenovirus vaccine candidate was responsible for the adverse events in 2 different patients. However, the FDA also did not conclude that there was no association between AZD1222 and the adverse events.

The decision, for now, concludes a 50-day series of safety reviews, international trial resumption, and debate over the standards of vaccine safety monitoring during an expedited COVID-19 vaccine development process.

The FDA originally announced its intent to review the US-based safety data for the vaccine in late September, at a time when late-stage international trials had resumed after the reported non-fatal event. The US-based research program, financially backed by Operation Warp Speed and including 30,000 US adults, was into phase 3 assessment at the time of being put on hold.​

Though many have used the used the reported safety issue—in which a patient in the UK was briefly hospitalized—to support an argument that COVID-19 vaccine development is too rushed, some experts were quick to point out the importance of there being a safety report halt in the first place.

Anthony Fauci, MD, director of the National Institutes of Allergy and Infectious Diseases (NIAID), told sister publication HCPLive last month that a trial pause for safety review is actually proof of a careful assessment system.

“This shows the system actually works, because when you do have a serious adverse event, the system allows you to immediately pick it up, put on a pause, examine what went on before you make a decision to proceed,” Fauci said. “It actually gives you comfort that the system is working, as opposed to you’re doing something that is inherently unsafe.”

Similarly, Bridget Calhoun, DrPH, MMS, Associate Dean for Academic Affairs and Research, and Chair and Associate Professor at Rangos School of Health Sciences at Duquesne University, told Contagion the FDA’s own independent review was a reflection of their adherence to scrutinous monitoring of vaccines—both at the development and regulation levels.

“Particularly in our democracy, we put a lot of faith in our national organizations,” Calhoun said. “So they have to be spot-on. They have to have reputable, responsible folks who are going to look at the data and make data-driven decisions based on the safety and efficacy of these vaccines.”