The U.S. health regulator has authorized COVID-19 shots from Moderna and Pfizer and its partner BioNTech that target both the original coronavirus and Omicron sub-variants for use in children as young as six months of age.
The amended authorization on Thursday from the U.S. Food and Drug Administration (FDA) allows use of Moderna’s bivalent shot as a booster in children six months through five years of age, two months after their initial vaccination.
Pfizer/BioNTech’s updated shot can now be given as a third dose to those aged six months through four years, who have not completed their primary vaccination series or are yet to receive the third dose.
Children who have completed their initial three-dose vaccination with Pfizer’s original shot are not yet eligible to receive the bivalent booster, the FDA said.
It added that data supporting use of Pfizer/BioNTech’s bivalent shot as a booster in this age group is expected in January.
Shots for youngest children in the United States were only approved in June this year, making them the last group to become eligible for vaccination.
In November, Health Canada approved Moderna’s updated vaccine for adults that includes a combination of two strains, also known as a “bivalent” shot. Pfizer’s bivalent version was approved by Health Canada a month earlier for those age five and up.
Both products contain the original vaccine formulation and protection against the Omicron subvariants BA.4 and BA.5.
Infectious disease physicians and public health officials say a booster dose is thought to offer better protection given immunity from vaccinations wanes over time.
As of Nov. 6, about 80 per cent of people completed the primary vaccination series in Canada, according to federal figures.
Uptake of vaccine doses in young children has been slower than among older age groups in both the U.S. and Canada. About 2.4 per cent of children under the age of four in Canada completed their primary vaccination series as did 41 per cent of those aged five to 11.