An advisory panel to the U.S. Centers for Disease Control and Prevention (CDC) is meeting on Thursday to discuss whether to recommend COVID-19 vaccine booster shots for children ages 5 to 11, a group that is just 29% vaccinated so far.

The U.S. Food and Drug Administration authorized booster doses of the Pfizer/BioNTech vaccine for those children on Tuesday as COVID cases are on the rise again in the United States.

The CDC's Advisory Committee on Immunization Practices (ACIP) could recommend making boosters available for some portion of that age group, but may stop short of saying all children should get the extra shot, experts said.

"Omicron and other Omicron-like variants have caused some degree of illness in children, but it has been less than Delta, so is there sufficient benefit (from a booster)?" said Dr. William Schaffner, who serves as the National Foundation for Infectious Diseases liaison to ACIP.

The companies submitted data to the FDA that showed a third dose of their vaccine generated a strong immune response against the Omicron variant in healthy children aged 5-11 years.

Severe disease is relatively rare in the age group, especially for those who have received two shots.

Dr. Paul Offit, a pediatric infectious diseases expert at Children's Hospital of Philadelphia, said boosters would likely have a limited impact on the pandemic, even though they may provide short-term protection against mild illness and some additional protection against serious disease for at-risk children.

The government has been pushing for eligible Americans to get boosted based on data showing vaccine immunity wanes over time.

If ACIP recommends the shots, CDC Director Rochelle Walensky is likely to quickly endorse the panel's view.

Just over 8 million of the estimated 28 million U.S. children aged 5-11 are considered fully vaccinated with two doses of the Pfizer/BioNTech shot. They are not yet authorized for children below age 5.

Companies are already looking into the possible need for a redesigned COVID vaccine in the fall. "So is it worth boosting these children now for a relatively low-risk period, before you perhaps recommend yet another booster this fall?" asked Schaffner. (Reporting by Manas Mishra in Bengaluru and Michael Erman in New Jersey; Editing by Bill Berkrot)