He said vaccine trials could begin within about three months.

We'll have to withdraw the vaccine trials and start all over again.

Their hypothesis is that the children were infected as part of a vaccine trial.

The day we were there the community held a meeting in an open field to discuss preparations for a vaccine trial.

As soon as they heard about the vaccine trials, the family did not hesitate.

Never mind that the Army thinks the vaccine trial is premature.

I know we can create a culture where going to vaccine trials is something that people want to do.

"We've had a hard time recruiting black and Latino men even for vaccine trials," he said.

A vaccine trial might involve forming two groups from the target population.