Many parents and doctors expected the Pfizer-BioNTech vaccine to be available for children ages 5 to 11 in early October.
That timeline for possible availability of shots prompted parents, public health experts and vaccine experts to anticipate shots as early as October.
Pfizer may not finish its application until mid-October, although the FDA may not make its decision until sometime between Halloween and Thanksgiving, according to a person familiar with the matter.
A spokesman said Pfizer submitted the data on Tuesday and is on track for a formal submission soon.
There is no vaccine yet authorized for children between the ages of 5 and 11. Many parents are eagerly waiting to vaccinate their children, especially since many have returned to schools.
The Biden administration and public-health experts are also looking forward to authorization for the younger age group, saying it could help reduce the spread of the infectious delta variant in addition to helping protect children in school.
The FDA said this month that it was “working around the clock” to help make COVID-19 shots available to children under the age of 12 but said the testing and regulatory process needed to come into play.
The agency is reviewing vaccine use data in child study subjects Pfizer previously submitted, the person said.
In their latest announcement, Pfizer and BioNTech said it provided FDA data from a positive recent late-stage study in young children for preliminary review.
The companies said last week that researchers in a pivotal study found a two-dose course of the vaccine to be safe and produce a stronger immune response in children ages 5 to 11. The companies said antibody levels in children who received the shot were similar to those measured in young adults in a separate study.
The Pfizer-BioEntech vaccine is approved in the United States for use in children under 12 years of age. The vaccination involves taking two doses at three-week intervals. If the FDA approves the vaccine for young children, it will be given at the same time, but young people will receive a lower dose than adolescents and adults.
Younger children have a lower risk of serious illness and hospitalization, but are going to hospital in greater numbers than ever before in the pandemic as the delta variant spreads.