(CNN) -- The first children have gotten Moderna's COVID-19 vaccine.
It's part of the pharmaceutical company's pediatric clinical trial.
About 6,700 children in the US and Canada between the ages of six months and 11 years old are participating.
They are getting two doses of the vaccine spaced about 28 days apart. As the trial continues, some children will be getting a placebo.
The US Food and Drug Administration authorized emergency use of Moderna's COVID-19 vaccine for adults in December.