Moderna COVID-19 vaccine
Moderna COVID-19 vaccineReuters

Moderna said on Sunday it has been told that the US Food and Drug Administration will require additional time to complete its assessment of the company's COVID-19 vaccine for use in adolescents aged 12 to 17 years, Reuters reports.

The FDA informed Moderna that the review may not be completed before January 2022, the company said in a statement.

Moderna Chief Executive Stephane Bancel told Reuters last week that based on conversations with the agency, he believed the vaccine would be authorized for those 12 to 17 in the next few weeks.

Moderna applied for US authorization of its vaccine for those aged 12 to 17 in June.

Two weeks ago it was reported that the FDA is delaying its decision on authorizing Moderna's COVID-19 vaccine for adolescents to check if the shot could increase the risk of heart inflammation.

The UK's health regulator approved Moderna's COVID-19 vaccine for use in children aged 12 to 17 years in August.

American adolescents are eligible for the Pfizer COVID-19 vaccine after it was cleared by the FDA and Centers for Disease Control and Prevention in May.