NEW YORK (BLOOMBERG) - US health officials approved Covid-19 vaccines for infants and toddlers, the last remaining age group that hasn't been eligible for inoculation.

The US Centres for Disease Control and Prevention's Advisory Committee on Immunisation Practices voted 12-0 on Saturday (June 18) to recommend Pfizer's three-dose vaccine for youngsters ages six months through four years.

They also voted 12-0 to recommend Moderna's two-dose vaccine for children six months through five years.

CDC director Rochelle Walensky signed off on the recommendations making the advice official and allowing the shots to finally go into arms.

Shots will be available at thousands of paediatric practices, pharmacies and other locations this week, the agency said.

President Joe Biden said the decision marked a "monumental step forward in the nation's fight against the virus."

"These vaccines are safe, highly effective, and will give parents the peace of mind of knowing their child is protected from the worst outcomes of Covid-19," Biden said in a statement.

The CDC endorsement is welcome news to the parents and caregivers who have been eager to give their youngsters some form of protection since vaccines first became available more than a year and a half ago.

However, the rate of vaccination for older children suggests that uptake is likely to be limited for toddlers. Only 29 per cent of American kids ages five to 11 have been fully vaccinated, according to CDC data, suggesting that some parents are hesitant or less motivated to inoculate their children.

During the meeting, CDC epidemic intelligence service officer Sara Oliver said the agency is trying to tackle this issue by making sure that information on the safety and effectiveness of these vaccines is available for parents.

For example, the agency will host clinician education calls and parent webinars as well as publish educational materials on social media.

"Making sure that parents feel that they have the appropriate information to make an informed decision about this is critically important," Oliver said.

Children are less likely than adults to experience the worst outcomes of Covid-19, and those under age five account for about 440 of more than one million related US deaths. Still, health officials warn, the rate of hospitalisation and death for children, particularly during the Omicron wave, has been concerning.

Data presented during Saturday's meeting showed that since the beginning of the pandemic, there have been over two million Covid-19 cases, 20,000 hospitalisations, and 200 deaths among US children ages six months to four years.

Combats severe disease

"We really want to get these children vaccinated, because we know vaccinations prevent infection, but to a greater extent prevent severe disease," Anthony Fauci, President Biden's medical adviser, said on Thursday, in a Senate hearing.

Moderna's two-dose vaccine was 51 per cent effective at preventing cases of Covid-19 for those under two years and 37 per cent effective for those ages two to five, the FDA said.

Common side effects of Moderna's shot include pain, injection site swelling and fever, the agency said. For Pfizer's, the most common side effects included irritability, decreased appetite and fever.

Parents and doctors may prefer Moderna's because of its higher efficacy after two doses, Cowen analyst Tyler Van Buren said in a note. Moderna's vaccine contains a higher dose of mRNA than Pfizer's.

The US government has already secured a supply of 10 million doses from Pfizer and Moderna to vaccinate under-fives.