The Food and Drug Administration (FDA) on Thursday announced it has expanded the emergency use authorization for the bivalent COVID-19 booster to include children between the ages of 6 months and 5 years.

With this announcement, children older than 6 months who have received the primary two-dose coronavirus vaccines from Moderna are now eligible to receive the bivalent booster specifically designed to protect against omicron subvariants of the virus.

Children who have not yet started on the primary series of Pfizer’s original coronavirus vaccines, which is administered in three doses for this younger age range, or have not yet received the final third dose are also eligible for the bivalent booster shot.

“More children now have the opportunity to update their protection against COVID-19 with a bivalent COVID-19 vaccine, and we encourage parents and caregivers of those eligible to consider doing so — especially as we head into the holidays and winter months where more time will be spent indoors,” FDA Commissioner Robert Califf said in a statement.

“As this virus has changed, and immunity from previous COVID-19 vaccination wanes, the more people who keep up to date on COVID-19 vaccinations, the more benefit there will be for individuals, families and public health by helping prevent severe illnesses, hospitalizations, and deaths,” he added.

According to the most up-to-date federal data, the BQ.1 and BQ.1.1 omicron subvariants are the two most common forms of the coronavirus circulating in the U.S. right now, collectively accounting for more than 60 percent of cases.

The bivalent boosters are expected to still be effective against these strains, as they descend from the BA.4 and BA.5 omicron subvariants.

The FDA previously authorized the bivalent booster shots for children as young as 5 in October, with officials at the time citing the return to school and the resumption of pre-pandemic activities for the need of the expanded vaccine coverage.

“Parents and caregivers can be assured that the FDA has taken a great deal of care in our review, and we encourage parents of children of any age who are eligible for primary vaccination or a bivalent COVID-19 vaccine booster dose to consider seeking vaccination now as it can potentially help protect them from COVID-19 during a time when cases are increasing,” Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, said.