In a pivotal development for school coronavirus safety, Pfizer-BioNTech announced Monday that its vaccine was safe and created a “robust” antibody response for children ages 5 to 11 in trials.

These are the first such results for this age group in the U.S., and data have not yet been peer-reviewed or submitted to the Food and Drug Administration for emergency use authorization. The pharmaceutical company plans to apply for approval to use the shot in children before the end of the month, the New York Times reports, meaning that millions of 5- to 11-year-olds could be inoculated before Halloween if the regulatory review goes as smoothly for this age group as it did for adolescents.

The trial included 2,268 participants ages 5 to 11 who were each given a two-dose regimen of the vaccine 21 days apart. Children were given a 10 microgram dose, smaller than the 30 micrograms administered to older children and adults, which the drug company said was a carefully selected dosage for safety, tolerability, and effectiveness.

One month after the second dose, the shots produced an immune response and side effects comparable to that delivered by the larger dose in 16- to 25-year-old patients, Pfizer said. A company spokesperson confirmed to CNN that there were no instances of myocarditis in the trial, a type of heart inflammation that has been linked with mRNA vaccines in boys and young men.

The results come at a pivotal time, as children now make up 29 percent of all new COVID cases and as the highly contagious Delta variant has sent more children into hospitals in the past few weeks than at any other point in the pandemic.

Already in the first weeks of the school year, tens of thousands of students have been forced out of class due to infection or exposure to the virus, oftentimes with sparse learning opportunities while they self-isolate. In Mississippi, where the state does not require that masks be worn in school, more than 4,500 students caught the virus in just one week and over 20,000 students and staff were in quarantine.

Read the full article about vaccine authorization for children by Asher Lehrer-Small at The 74.