Coronavirus vaccines speed ahead — but scientists stress safety first

By Denise Chow

With the world waiting for a coronavirus vaccine, scientists know the stakes couldn't be higher.

Three vaccines are in phase 3 of human clinical trials, which ensure effectiveness but also safety — a crucial element as an accelerated timeline, mounting numbers of cases and deaths and no shortage of misinformation have added enormous pressure to the process.

Any approved vaccine will be the subject of intense scrutiny.

"There's a real danger in approving a vaccine that doesn't work well enough," said Natalie Dean, an assistant professor of biostatistics at the University of Florida in Gainesville. "We have to do it right the first time. The public trust is very important in the long term, and people need to be confident that it's an adequately effective product."

All vaccines are thoroughly tested before receiving final approval, with a new vaccine typically taking around 10 years to go through the development and testing stages. That includes extensive testing to ensure that side effects are minimal.

But the coronavirus vaccine process has been anything but typical. The urgency of the pandemic means vaccine researchers are shortening or eliminating downtime between trial phases and collaborating in ways rarely seen in what can be a competitive field.