Moderna plans to submit an application to the US health regulator for emergency use authorization (EUA) of its Covid-19 vaccine among kids between the ages of six months to five years by end of the month, a company spokesperson told Reuters on Wednesday.

The Omicron variant was predominant during Moderna's pediatric trial, and the drugmaker said two doses were around 38 per cent effective in preventing infections in 2 to 5-year-olds and 44 per cent effective for children aged 6 months to under 2 years.

Last week, Pfizer Inc and BioNTech said a third dose of the Covid-19 vaccine produced significant protection against the Omicron variant in healthy children from ages 5 to 11.

Earlier this year, the US Food and Drug Administration authorized a third dose of the Pfizer/BioNTech vaccine for children ages 12 to 15 and those aged 5 through 11 who are immunocompromised.