Children as young as five in the United States will now be able to receive a booster dose of Pfizer's Covid-19 vaccine, the nation's health authorities announced Tuesday.

The US Food and Drug Administration authorized children in the 5-11 group to receive the booster in order to "provide continued protection against Covid-19," FDA Commissioner Robert Califf said in a statement.

A committee of experts from the US Centers for Disease Control and Prevention (CDC) is scheduled to meet Thursday on the issue.

Children will become eligible for the booster at least five months after completing their initial vaccine doses. The dosage is 10 micrograms for both the initial shots and the booster, compared to 30 for those 12 and older.

The authorization comes as Covid cases are on the rise in the United States, with approximately 90,000 cases reported per day. Hospitalizations are also up.

"While it has largely been the case that Covid-19 tends to be less severe in children than adults, the omicron wave has seen more kids getting sick with the disease and being hospitalized, and children may also experience longer term effects, even following initially mild disease," Califf said.

There are 28 million children who fall into the 5-11 age range in the United States, and there have been 4.8 million Covid cases and about 360 deaths among them so far, according to CDC figures.

This age group has been eligible to receive the initial two doses of Pfizer's vaccine since November 2021, but less than 30 percent of them have so far.

The FDA on Tuesday again emphasized the importance of vaccination to prevent severe cases of Covid-19.

Children under five are not yet eligible for vaccination, but an independent panel of experts is scheduled to meet in June to review clinical trial data from Pfizer and Moderna about this age group.