Pfizer Inc and its German partner BioNTech SE on Friday sought the permission of U.S. regulators for emergency use of their vaccine in adolescents aged 12 to 15.

The vaccine is currently authorized for emergency use in the United States for those who are 16 and above. The companies said on Friday that they requested an expansion of the authorization from the U.S. Food and Drug Administration to include the younger age group.

The pharma giants said the vaccine was found to be safe, effective and produced robust antibody responses in 12 to 15-year-olds in a clinical trial that was heel din March.

The regulator said it does not plan to hold a meeting of the independent advisory board that recommended the vaccine’s initial authorization, for expanding its use in adolescents.

Moderna Inc and Johnson & Johnson are also testing their vaccines in 12 to 18-year-olds, and data from Moderna’s trial is expected soon.

Pfizer and Moderna have also launched trials in younger children, aged six months to 11 years old. Both companies have said they hope to be able to vaccinate children under 11 by 2022.

Inoculating children and young people is considered a critical step toward reaching herd immunity and taming the pandemic, according to many experts.

Pfizer and BioNtech said they also plan to ask regulatory authorities of other countries to allow the use of their vaccine in 12 to 15-year-olds in days ahead.