Pfizer is opening up its vaccine trials to include children as young as 6 months old.

The Rockland-based company plans to enroll up to 4,500 children.

The study opened Tuesday at Stony Brook Children's Hospital on Long Island and is now taking applications for volunteers.

Participants will get two shots of smaller doses.

Pfizer is authorized in the U.S. for children 12 and older.

Moderna says its COVID-19 vaccine will likely be available for children as young as 5 in the early fall.

The company is also testing its shots in children as young as 6 months old.