Ottawa, Feb 18 : Health Canada announced that it has authorized the use of Moderna's Spikevax bivalent Covid-19 booster vaccine for children and adolescents aged six to 17 years of age targeting the Omicron variant BA.1. A booster dose of 50 micrograms may be administered in individuals 12 years of age and older at least 4 months after completing their primary vaccine series or a previous booster dose and a booster dose of 25 micrograms in children 6 to 11 years of age at least 6 months after completing their primary vaccine series or a previous booster dose, Xinhua news agency quoted the health body as saying. "The authorization of a booster dose in children and adolescents is a critical step to broaden protection against the Omicron family of variants, and the emergence of new variants of concern in Canada," said Stephane Bancel, chief executive officer of Moderna, in a news release. The BA.1 booster was previously approved for people aged 18 and over. Moderna's Omicron-targeting bivalent booster for variant BA.4/5 has not yet been approved for use in people under 18 years of age. /IANS