The U.S. Centers for Disease Control and Prevention (CDC) on Wednesday recommended updated Omicron-targeting COVID boosters for Americans as young as 5-years-old, seeking to increase protection ahead of the colder months.

CDC Director Dr. Rochelle Walensky recommended the shots for children soon after the U.S. Food and Drug Administration (FDA) authorized them on Wednesday.

The bivalent vaccines--which target both the original strain of the COVID virus and its highly contagious Omicron subvariants BA.4 and BA.5--provide better protection against the currently dominant circulating strain as health officials prepare for an expected winter surge in infections as more people hold gatherings indoors.

Under the recommendation, children ages 5 to 11 are eligible for Pfizer's (PFE  ) omicron shots and those ages 6 through 17 are eligible for Moderna's (MRNA  ) shots at least two month after receiving their primary series or previous third dose booster of the original COVID vaccines.

"Since children have gone back to school in person and people are resuming pre-pandemic behaviors and activities, there is the potential for increased risk of exposure to the virus that causes COVID-19. Vaccination remains the most effective measure to prevent the severe consequences of COVID-19, including hospitalization and death," said Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, in a statement Wednesday.

"While it has largely been the case that COVID-19 tends to be less severe in children than adults, as the various waves of COVID-19 have occurred, more children have gotten sick with the disease and have been hospitalized," Marks added. "Children may also experience long-term effects, even following initially mild disease. We encourage parents to consider primary vaccination for children and follow-up with an updated booster dose when eligible."

The FDA authorized the updated shots for younger Americans without direct human trial data on their effectiveness, instead using data from an adult study of a similar how that targets the Omicron BA.1 subvariant. The federal agency also looked at clinical data in children who received the original vaccines as booster shots.

The CDC's decision allows pharmacies to begin administering the booster shots as soon as they are on hand. Pfizer said in a statement Wednesday that is will ship up to 6 million doses for children within the next week.