Vaccine Trial for Children Under Age 12 Has Begun, Pfizer Says

Pfizer Inc. said that dosing has begun in a pediatric study of its Covid-19 vaccine, a trial that will ultimately involve more than 4,500 children under age 12.

The two-part trial will first study three dose levels in 144 children from age 6 months to 11 years, the company said in a statement Thursday. Once an appropriate dose is established for each of three age groups, 4,500 more kids in the U.S. and Europe will be enrolled in the second part of the trial, which will look at safety tolerability and immunogenicity of the vaccine, the company said.

Two-thirds of ...