The director of the U.S. Centers for Disease Control and Prevention (CDC) on Thursday endorsed an advisory panel’s decision to expand the eligibility of Pfizer booster shots to children aged 5 to 11.

CDC Director Rochelle Walensky made the call after a meeting of the Advisory Committee on Immunization Practices voted to advise the CDC to recommend the booster. Walensky said children in this age group were otherwise at risk of severe disease.

“Children five through 11 should receive a booster dose at least five months after their primary series. Vaccination with a primary series among this age group has lagged behind other age groups leaving them vulnerable to serious illness,” she said in a release.

The protection the first two doses, or the primary series, provide has been shown to wane over time. The effect of boosters, particularly against infection, quickly wanes, studies show.

Walensky encouraged parents to keep their kids up to date with COVID shots, saying that after more than 18 million jabs were already given to children, the evidence was that “these vaccines are safe.”

A number of side effects have cropped up for the vaccines, including heart inflammation.

The need for children to get a COVID jab has been disputed by an infectious disease expert at the University of California, and others in the United States and abroad.

“There is no evidence that children 5-11 years old need a booster shot of the vaccine, nor of demonstrated benefit,” Dr. Monica Gandhi previously told The Epoch Times via email.

The CDC’s recommendation comes days after the U.S. Food and Drug Administration granted emergency approval to give the shots to children as young as five.

In announcing the emergency authorization on May 17, FDA Commissioner Robert Califf admitted that while COVID-19 “has largely” been “less severe in children,” the Omicron strain had given rise to concern about the risk of children getting ill, ending up in the hospital, and experiencing “longer term effects.”

The data supporting Califf’s claims were taken from a sample of only 67 study participants who received a booster dose seven to nine months after completing a two-dose primary series of a Pfizer shot.

The CDC is now also recommending that anyone over 50 years old or over 12 and immunocompromised “should get a second booster dose” at least four months after the first.