Pharmaceutical company Moderna said on Tuesday that its coronavirus vaccine was found to be safe and effective on children aged between 12 and 17.

In its phase 2/3 trial, the company evaluated the vaccine on 3,732 participants. Two-third of them were given the vaccine while one-third got a placebo, Moderna said in a statement. The company was aiming to produce an immune response similar to that seen during the large trials in adults, where the vaccine was found to be 94.1% effective at preventing Covid-19.

During the trial on the children, the researchers found out that the vaccine was 100% effective 14 days after receiving the second dose, according to the company’s case definition used in the adult trial. The statement said that after two doses of the vaccine, no cases were reported in the children, while the participants who were administered placebo had four cases of the infection.

However, the vaccine was found to be 93% effective, based on the United States’ Centers for Disease Control and Prevention case definition that takes into account milder symptoms.

The company also said that no major safety concern was reported in the trial. It said that adverse cases were mild or moderate in severity. The most common side effects were headache, fatigue, myalgia and chills, Moderna said.

“We are encouraged that mRNA-1273 [the vaccine] was highly effective at preventing Covid-19 in adolescents,” Moderna’s Chief Executive Officer Stephane Bancel said. “We will submit these results to the US FDA [Food and Drug Administration] and regulators globally in early June and request authorization. We remain committed to doing our part to help end the Covid-19 pandemic.”

The statement said that the company was also planning to submit the data from the trial to a peer-reviewed publication.

If the vaccine is approved in the US, it will become the second option for vaccinating children aged between 12 and 17. The US and Canada have approved a Covid-19 vaccine made by pharmaceutical firm Pfizer and biotechnology company BioNTech for the age group, reported AP.