Parents Flocked to Vaccine Trials, Now Wait for Teen Jab Options

Parents drove hours to get their kids into a Covid-19 vaccine clinical trial in Houston. One call even came from New York City.

“My name somehow came up, and she wanted to bring her child,” pediatric infectious disease specialist Flor M. Munoz recounted. She directed that parent to a closer site but said requests to participate in her study have come in from Austin and other Texas towns hours away.

Munoz, who has been running clinical trials for 25 years, knows firsthand how difficult it can be to accrue enough participants to run vaccine studies. The pandemic changed that. Parents ...