July 27 (UPI) -- Pfizer and Moderna have been asked by federal regulators to expand the size of the studies of their respective COVID-19 vaccines to include more children between the ages of 5 and 11, according to news reports.
The request is as a precautionary measure to detect rare vaccine side effects like heart inflammation that were seen in some vaccinated people under 30.
Moderna spokesman Ray Jordan told the Times that the company intends to expand its trials and seek emergency authorization late this year or early next.
"The objective is to enroll a larger safety database which increases the likelihood of detecting rarer events," he told CNN.
Pfizer may be able to receive emergency authorization and see results for the 5-to-11 group by the end of September.
The FDA said existing studies for both vaccines are inadequate in detecting rare side effects. In June, the Centers for Disease Control and Prevention published data showing that the two vaccines may have caused heart inflammation in more than 1,200 Americans, many of whom were under 30.
More trial and study results on both vaccines have been published in recent weeks.
A few days ago, studies showed that the Pfizer vaccine was effective against the highly infectious Delta variant. Earlier this month, it was also found effective in patients with cancer.