Moderna expanding kids vaccine study to better assess safety

Moderna plans to expand the size of its COVID-19 vaccine study in younger children to better detect rare side effects

WASHINGTON -- Moderna said Monday it plans to expand the size of its COVID-19 vaccine study in younger children to better detect rare side effects, such as a type of heart inflammation recently flagged by U.S. health authorities. The company said it is in talks with the Food and Drug Administration to enroll more study participants under age 12. It had intended to test the vaccine in about 7,000 children, with some as young as 6 months. The Cambridge, Massachusetts-based company said via email it hasn't decided on how many kids might be added. The announcement comes as U.S. COVID-19 cases are rising and schools prepare to welcome students back to classrooms. At the same time, regulators continue to review cases of a rare type of heart inflammation called myocarditis that has been reported in a small number of teenagers who got the Moderna or Pfizer shots. Pfizer said on Monday that if it makes changes to its vaccine testing in children, it will provide an update then. The New York-based company is testing its vaccine in up to 4,500 children in the United States and Europe.