The move comes as the Omicron variant wave is waning in the United States.
Pfizer and BioNTech will soon ask US regulators for emergency authorization for a Covid-19 vaccine for children aged five and under, US media reported Tuesday.
This is the last age group in the United States that is not yet eligible for coronavirus shots.
As early as Tuesday, the companies could seek emergency authorization for a two-dose vaccination regimen for children under five and as young as six months, The New York Times and other news outlets said.
The move comes as the Omicron variant wave is waning in the United States but parents are still grappling with school closures and concerns for their unvaccinated children.
New pediatric Covid hospitalizations hit a record high in the United States in December as the Omicron strain spread rapidly.
Last month, the Food and Drug Administration approved Pfizer's Covid-19 booster shot for children as young as 12.
But vaccination rates among this age group are relatively low -- less than 22 percent, according to the Centers for Disease Control and Prevention.
As they seek the green light for children under five to receive two doses of the vaccine, Pfizer and BioNTech will also continue studies on a three-shot regimen, the Times said.
The FDA hopes to approve shots for young kids as early as late February. Data on a three-dose regimen would not be submitted until late March, the daily added.
The companies concluded last fall that low doses of the vaccine provided protection in children up to two years old but not in kids aged two to five, announcing in December they would add a third dose to their trials.
"We know that two doses isn't enough, and we get that," a source told The Washington Post.
"The idea is, let's go ahead and start the review of two doses. If the data holds up in the submission, you could start kids on their primary baseline months earlier than if you don't do anything until the third-dose data comes in."