While it's not common for vaccine candidates that have delivered good results in early stages to fail in subsequent phases, it can happen.
An employee is seen at the Reference Center for Special Immunobiologicals of the Federal University of Sao Paulo where the trials of the Oxford/AstraZeneca coronavirus vaccine are conducted, in Sao Paulo on June 24, 2020.Amanda Perobelli / Reuters
By Denise Chow
Two potential coronavirus vaccines have shown promising results in early trials, and while experts say it's encouraging news, they warn that some of the biggest hurdles still lie ahead.
The early trial results for the two vaccine candidates — one developed by the University of Oxford and AstraZeneca and the other by the Chinese company CanSino Biologics — showed that both were safe and could induce immune responses in participants. But the next phase will be critical to demonstrate that the potential vaccines can protect against infections.
"If we're making a plane, right now we're at the production level," said Dr. Carlos del Rio, executive associate dean of the Emory University School of Medicine in Atlanta. "We can say it looks like this can at least get off the ground and do so safely. But can it get me from here to Paris? That's the question now." Read more >>