The US Food and Drug Administration announced today (June 17) that it has amended emergency use authorizations for both the Moderna and Pfizer-BioNTech vaccines to include children as young as six months old.

“Many parents, caregivers, and clinicians have been waiting for a vaccine for younger children and this action will help protect those down to six months of age,” FDA Commissioner Robert Califf says in the agency’s news release.

The FDA’s announcement comes days after an independent advisory committee of health experts voted 21 to 0 to expand vaccine access, reports The Wall Street Journal. Prior to the FDA’s action today, use of the Moderna vaccine was restricted to adults aged 18 years and older, while the Pfizer-BioNTech vaccine had been authorized for kids who are 5 years of age and older, the agency says in its release. Now, everyone aged six months and older will be eligible for either of the two vaccines.

The FDA’s press release says that the clinical trial data used to evaluate the Pfizer-BioNTech vaccines found that the immune responses of children between the ages of 6 months and 5 years given three doses were comparable to adults given two doses. According to Pfizer, the dosage used in the trial for children was one-tenth that used for adults.

The FDA’s announcement also says that clinical trial data for the Moderna vaccine showed that children and adolescents 6 to 17 years of age given two doses showed immune responses comparable to those of adults receiving the same number of shots at the same dosage. For adolescents 12 to 17 years old, the regimen was 93 percent effective at preventing COVID-19. In children between the ages of 6 and 23 months, a two-vaccine regimen, with each being one quarter the adult dose, was 51 percent effective at preventing COVID-19. Furthermore, for kids who were two through five years of age, giving two doses of half the amount used on adults was 37 percent effective at preventing COVID-19.

A Moderna spokesperson tells CNN that it’s currently investigating a third shot for children. “I think all of us agree that these children are going to need a third dose at some point in time,” Jacqueline Miller, Moderna’s senior vice president of infectious diseases, tells the outlet.

In its press release, the FDA writes that the Moderna vaccine will be given to children and adolescents as two injections spaced one month apart, and a third dose may be given to immunocompromised children one month following the second shot. For the Pfizer-BioNTech vaccine, the first two doses are given three weeks apart with the third given at least eight weeks after the second.

Both vaccines were reportedly “well-tolerated” in children, according to CNN. The FDA announcement states that the most common side effects for the Pfizer-BioNTech vaccine were irritability, decreased appetite, fever, and pain at the injection site. For the Moderna vaccine, common side effects were similar, including pain at the injection site, headache, and muscle and joint pain.

Shots cannot be administered until the Centers for Disease Control and Prevention (CDC) votes to recommend them, according to CNN, but the agency is expected to vote this Saturday (June 18). The White House has previously said that these vaccinations for kids could become available as soon as June 21, reports the Journal.

Ofer Levy of Boston Children’s Hospital, who serves on the FDA’s advisory committee, tells CNN, “I’m really pleased that we’ve reached this kind of milestone.”