The Pfizer-BioNTech and the Moderna Covid-19 vaccines are both safe and effective in children ages 6 and younger, according to FDA, meaning the shots could be available for young children very soon.

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Details on the vaccines' effectiveness

According to FDA, the Pfizer-BioNTech vaccine was 75.6% effective in preventing symptomatic Covid-19 among children ages 6 to 23 months, 82.4% effective among children ages 2 to 4, and 80.4% effective in a combined analysis of both age groups.

Meanwhile, Moderna's vaccine was found to be 51% effective in preventing symptomatic Covid-19 among children ages 6 months to 2 years old and 37% effective among those ages 2 to 5 years old.

Among adolescents, Moderna's vaccine was 93% effective in a study conducted during the circulation of the original coronavirus strain and the alpha variant, FDA said. While the delta variant was prominent, Moderna's vaccine was 77% effective among children ages 6 to 11.

FDA found that children ages 11 and younger experienced fewer side effects than adolescents, likely because the doses were weaker. Fevers were more frequent among children ages 6 and under; however, the rates of fevers weren't significantly different than the rates of fevers produced by other childhood vaccines, FDA said. Among recipients of both vaccines, there were no cases of myocarditis or pericarditis.

FDA advisers are scheduled to meet early this week to determine whether they will recommend Moderna's vaccine for children ages 6 months to 17 years and Pfizer-BioNTech's vaccine for children under the age of 5. Meanwhile, a CDC advisory committee is scheduled to meet Friday and Saturday to discuss the vaccines

US orders millions of vaccines for children

In anticipation of federal authorization this week, the White House announced that millions of Covid-19 vaccine doses for young children have been made available for states and health care providers to order.

As of last week, roughly 1.45 million doses of the Pfizer-BioNTech vaccine and around 850,000 doses of the Moderna vaccine have been ordered out of an initial 5 million available doses, White House officials said.

According to Ashish Jha, White House Covid-19 coordinator, if both FDA and CDC authorize the vaccine, vaccinations could begin as early as June 21. "We have waited a long time for this moment," Jha said. (Falconer, Axios, 6/12; Knutson, Axios, 6/10; LaFraniere, New York Times, 6/11; Loftus, Wall Street Journal, 6/10; Stobbe, Associated Press, 6/9)