Some vaccine trials were paused--does that mean the vaccines are dangerous?

You are probably hearing a lot about vaccines for COVID-19. You may have heard that some of these vaccine trials were paused. You may be wondering if this means the vaccines are dangerous. 

Prior to beginning any vaccine trial, doctors develop rules about when to temporarily stop the trial in case of safety concerns. Pauses in clinical trials show that study investigators take safety seriously. And both COVID vaccine trials that were paused, the Johnson & Johnson and AstraZeneca, restarted their trials. That means that doctors determined that the vaccines were not the cause of the illnesses. 

The two vaccines that will start rolling out doses in the coming weeks, produced by Moderna and Pfizer, have also been shown to be safe. Vaccines are an important step in combating the pandemic. But lots of people, including doctors and government agencies around the world, are committed to making sure they’re safe before they get rolled out.

Last update: December 18, 2020, 4:04 pm ET

Science review: ERS, JAB