Moderna announced on Tuesday that its Covid-19 vaccine provides good protection to children as young as 12, putting the vaccine on track to become the second choice for that age group in the United States.

In order to end the pandemic, much of the world is now unable to vaccinate adults due to a lack of vaccine supply. However, earlier this month, the US and Canada approved the use of another vaccine — the Pfizer and BioNTech shot — beginning at the age of 12.

Moderna says it will send the teen data to the US Food and Drug Administration and other international regulators early next month.

More than 3,700 12- to 17-year-olds were studied by the firm. According to preliminary results, the vaccine elicited the same symptoms of immune protection in children as it does in adults, as well as the same types of temporary side effects like sore muscles, headaches, and exhaustion.

There were no COVID-19 diagnoses among the children who received two doses of the Moderna vaccine, compared to four cases among the children who received dummy shots. In a press release, the firm also stated that two weeks after the first injection, the vaccine seemed to be 93 percent safe.

Although children are much less likely than adults to become chronically ill as a result of COVID-19, they account for around 14% of all coronavirus cases in the United States. According to the American Academy of Pediatrics, at least 316 children have died in the United States alone.

With enough vaccine supplies in the United States, younger teenagers flocked to get Pfizer’s shot in the days after the FDA approved it, part of a drive to get as many children vaccinated as possible before the start of the next school year.

Pfizer and Moderna have both started experimenting with much younger infants, from 11 months ago to 6-month-old babies. This testing is more complicated: teenagers are given the same dosage as adults, but younger children are given lesser doses.