Moderna Inc. said Tuesday its coronavirus vaccine has proven effective in adolescents between the ages of 12 and 17, raising the prospects of it becoming the second vaccine authorized for use on the age group in the United States.

The U.S. biotechnology firm plans to submit the results of the study to regulators at home and abroad in early June to seek authorization. Its vaccine has so far been granted an emergency use authorization for individuals 18 or older.

In the study involving more than 3,700 participants aged 12 to 17 in the United States, no coronavirus infections were observed among those who received the two-dose vaccination while four cases were detected in those who received dummy shots, the company said in a press release.

No significant safety concerns have been identified to date. Common adverse reactions after vaccination included injection-site pain, headache, fatigue and chills, but the majority of such symptoms were mild or moderate in severity, Moderna said.

Earlier this month, U.S. regulators authorized the emergency use of Pfizer Inc.'s vaccine for adolescents as young as 12 years old, lowering the minimum age from 16.

The expansion of age groups eligible to receive vaccines is expected to help protect junior and senior high school students from COVID-19, the respiratory illness caused by the novel coronavirus.

The Japanese government last week joined other countries in approving the vaccine developed by Moderna, with its use greenlit for people aged 18 or older.

Japan launched its inoculation drive in February, using Pfizer's vaccine, starting with health care workers and later expanding to people aged 65 and older. But vaccination in the country has lagged behind other developed nations.

Moderna's vaccine, like the one developed by U.S. pharmaceutical giant Pfizer and its German partner BioNTech SE, uses a new technology known as messenger RNA, or mRNA.

While traditional vaccines put a weakened or inactivated germ into human bodies to trigger an immune response, mRNA vaccines give instructions for cells to make a harmless "spike protein" that resembles one found in the novel coronavirus.

The immune system then detects the protein and starts building an immune response and making antibodies to protect against future infection.