Pfizer and BioNTech have begun submitting a formal request to United States health regulators for emergency use of their Covid vaccine for children aged over six months and under five years.
If the Food and Drug Administration (FDA) authorises the two-shot regimen, it will become the first COVID-19 vaccine available to this age group in the United States.
In a tweet soon after the announcement, the FDA said it will hold a meeting on 15 February to consider the request.
The companies are seeking authorisation for only two doses of their vaccine, but believe a third will be needed "to achieve high levels of protection against current and potential future variants," Pfizer CEO Albert Bourla said in a statement.
"If two doses are authorised, parents will have the opportunity to begin a COVID-19 vaccination series for their children while awaiting potential authorization of a third dose," he added.
To limit side effects for this young age group, Pfizer chose to significantly decrease the dosage of its vaccine, opting for only three micrograms per jab versus 30 for those over 12 years old, and 10 for ages five to 11.
The company's researchers concluded last fall that low doses of the vaccine provided protection in children up to two years old but not in those aged two to five, and announced in December they would add a third dose to their trials.
Data on the three-dose regimen is "expected in the coming months and will be submitted to the FDA to support a potential expansion" of this initial request, Pfizer and BioNTech said in a press release.
Two years into the pandemic, many parents are waiting impatiently to vaccinate their young children against the coronavirus.
The Pfizer-BioNTech vaccine was approved three months ago for emergency use in children from five to 11.
