Moderna intends to expand a COVID-19 vaccine trial among kids under 12 to better monitor for potential rare side effects, a spokesperson confirmed to Fox News.

"It is our intent to expand the trial and we are actively discussing a proposal with the FDA," a Moderna spokesperson wrote to Fox News in an email. "The objective is to enroll a larger safety database which increases the likelihood of detecting rarer events."

"At this point we expect to have a package that supports authorization in winter 2021/early 2022, should the FDA choose to use the authorization avenue," the statement continues in part.


The news comes after The New York Times reported earlier Monday that, at the "urging" of the FDA, Pfizer and Moderna were broadening the "size and scope" of their respective trials in kids aged 5-11 in a "precautionary measure" to spot rare adverse events post-vaccination, including heart inflammation. The newspaper, citing one anonymous individual, said the agency requested that companies include 3,000 kids in the 5-11 cohort, said to double the initial size.

When prompted by Fox News, an FDA spokesperson wouldn’t elaborate on interactions with drug sponsors, writing, "While we cannot comment on individual interactions with sponsors, we do generally work with sponsors to ensure the number of participants in clinical trials are of adequate size to detect safety signals."

A Pfizer spokesperson said the company expects early results of late stage trials in September for participants aged 5-11, with results for younger age groups, 2-5, expected "shortly after." Findings among children as young as six months are expected in October or November. 

"Pfizer has not provided any updates to the previously stated timelines," reads a statement shared with Fox News. "Pfizer began testing its COVID-19 vaccine in 5-11 year old children on June 8, 2021, with those younger than 5 starting June 21, 2021. The study will include up to 4,500 participants from the United States, Finland, Poland and Spain."


Dr. Alejandra Gurtman, vice president of vaccine clinical research and development at Pfizer, last month noted company plans to vaccinate 4,500 participants with two doses spaced 21 days apart. In the same virtual symposium led by Johns Hopkins University-University of Washington, Dr. Sabine Schynder Ghamloush, director of clinical development at Moderna, said the company was in the first part of KidCOVE, Moderna’s pediatric trial, at the time said to involve about 7,000 children between 6 months to 11 years of age.