This will be the first coronavirus vaccine trial to include children in the United States.
The Vaccine Research Center at Cincinnati Children's Hospital says teens ages 16 and 17 will get the vaccine this week.
Kids between the ages of 12 and 15 will be enrolled in the trial later.
The company confirmed on its website it has approval from the U.S. Food and Drug Administration to enroll children as young as 12 in its trial.
The expansion in age groups comes a month after the company enrolled approximately 44,000 participants in a vaccine trial, according to Pfizer.
CNN contributed to this report.
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