Pfizer Inc said on Monday its Covid-19 vaccine provided strong long-term protection against the virus in a late-stage study conducted among adolescents aged 12 to 15 years.

A two-dose series of the vaccine was 100% effective against Covid-19, measured seven days through over four months after the second dose, the company said.

The long-term data will support planned submissions for full-regulatory approval of the vaccine in the age group in the United States and worldwide.

Pfizer and BioNTech will seek clearance for a 30 micrograms dose of the vaccine for those aged 12 and above.

The vaccine was authorized for emergency use in people aged 12-15 years by the US Food & Drug Administration in May, and granted full approval for use in people aged 16 and above in August.