Pfizer-BioNTech said on Monday that the companies’ two-dose Covid-19 vaccine was safe and showed a “robust” antibody response in children ages 5 to 11.

Based on data collected in a trial that included more than 2,000 children, Pfizer and its German partner, BioNTech, said in a press release that the vaccine was “safe, well tolerated, and showed robust neutralizing antibody responses” for this age group. No Covid vaccines have yet been authorized or approved for use in children under 12.

The children in the trial were given two smaller doses of the vaccine than those given to people 12 and older, according to the release. The companies said that it produced antibody responses, and side effects, in children that were comparable to those seen in a study of people 16 to 25 who received the full dose of the vaccine.