Pfizer (PFE  )-BioNTech (BNTX  ) and Moderna's (MRNA  ) COVID vaccines for infants and young children are now one step closer to authorization, as the U.S. Food and Drug Administration's (FDA) committee of independent vaccine expects unanimously voted to recommend the shots for the youngest Americans.

The panel made the recommendation after discussing the safety profile and efficacy of both vaccines during an all-day meeting. Moving forward, the FDA will likely support the committee's decision and expand each companies' emergency use authorization. Then, the U.S. Centers for Disease Control and Prevention (CDC) will need to sign off on the shots before they can be distributed to pharmacies and other health care centers to be administered to children.

COVID infections have been generally less severe in children than adults, but hospitalization rates for children under 5 rose during the initial wave of Omicron earlier this year. Children under 5 are the only age group still ineligible for vaccination in the U.S.

While the underlying technology behind both Pfizer and Moderna's vaccines are the same, the shots for young children differ in a few ways, including how many doses are administered and their efficiency.

Pfizer's vaccine is given in a series of three 3 microgram dose (one-tenth the dosage for adults) for children ages six months to 4-years-old. The vaccine demonstrated about 75% efficiency against Omicron in infants to children ages 2-years-old, and 82% effective for those ages 2- to 4-years-old.

Moderna's vaccine is administered in the standard two-dose series of 25 micrograms (one-fourth the dosage for adults) for children between the ages of six months and 5-years old. The vaccine was about 51% effective against Omicron for kids under 2-years-old and about 37% effective for children aged 2- to 5-years-old.

Moderna plans to publish data on efficiency of a third dose targeting Omicron in young children this quarter and submit data to the FDA to review as soon as possible, said Dr. Jacqueline Miller, senior vice president of infectious diseases at Moderna, CNBC reports.

The vaccines produced similar safety profiles, with common side effects being injection site pain, irritability and crying, loss of appetite, and fatigue, according to the FDA. A small amount of children developed high fevers greater than 102 degrees Fahrenheit, or 39 degrees Celsius, but no other adverse effects occurred.