(Reuters) – U.S. Food and Drug Administration said on Friday clinical trials testing COVID-19 vaccines for children are expected to include a monitoring period of at least two months after half the participants get the shots to ensure safety.

The comments come as vaccine makers race to submit clinical data seeking regulatory approval for the use of their vaccines in children below 12, as schools around the country begin to reopen for in-person learning.

German drugmaker and Pfizer Inc’s partner, BioNTech SE, earlier on Friday said it was set to request approval across the globe to use its COVID-19 vaccine in children as young as five over the next few weeks.

“Children are not small adults – and issues that may be addressed in pediatric vaccine trials can include whether there is a need for different doses or different strength formulations of vaccines already used for adults,” FDA Acting Commissioner Janet Woodcock said in a joint statement with the director of Center for Biologics Evaluation and Research.

(Reporting by Manojna Maddipatla in Bengaluru)