New Orleans has become one of the first major U.S. cities to mandate COVID-19 vaccination for eligible children ages 5 and up in order to attend school.

The requirement went into effect Tuesday, though families may claim an exemption for philosophical, religious or medical needs, according to New Orleans public school districts.

"We all know that vaccines are the best tool that we have at our disposal at this time to keep our children in the classroom so that they can learn so that they can grow with their teachers as well as their friends," NOLA Public Schools Superintendent Henderson Lewis Jr. said during a press conference last December, when the mandate was announced.

A representative for NOLA Public Schools told ABC News that school officials will work to help students either complete their vaccination regimens or notify their schools that they are claiming an exemption. Students will not be removed or kicked out of class if they do not get vaccinated.

"The goal is not to deny educational opportunities to any child," the representative said in a statement Tuesday evening. "But we need parents and families to let us know where they stand -- either fully vaccinated, partly vaccinated, or exempt -- so that our schools can better plan around potential quarantines and limit future disruptions to students’ schooling as this pandemic continues. The deadline is about encouraging our families to take a personal stake in helping to keep safe our entire school community."

About 56% of 5 to 17 year olds in New Orleans have received their first dose of a COVID-19 vaccine, while approximately 40% are fully vaccinated, according to the public school district. Beginning Tuesday, the Louisiana city will also require children ages 5 and up to show proof of COVID-19 vaccination or a negative COVID-19 test to enter certain establishments.

-ABC News' Arielle Mitropoulos

The FDA's advisory committee will meet on Feb. 15 to review the Pfizer vaccine for use in children under the age of 5. The advisory committee is an independent group whose vote is nonbinding, but the FDA takes it into consideration when making a final decision.

The vaccine would still need to go through several other approvals before it can be used on children under the age of 5. It would need to be authorized by the FDA, then the CDC advisory committee would need to meet for recommendations and it would need to be approved by the CDC.

Pfizer and BioNTech said Tuesday they have initiated rolling submission for emergency use authorization for kids 6 months through 4 years old -- at the request of the FDA. Pfizer and BioNTech said they're submitted data for two doses but expect the vaccine to be a three-dose series, and that the data for the third dose will be provided in the coming months.

The federal government has shipped 100 million free N95 masks so far, according to the White House, after the Biden administration announced on Jan. 19 that it would provide 400 million free N95 masks to Americans.

-ABC News' Ben Gittleson

A new study from Los Angeles County's health department estimates that during the city's omicron surge, people who were unvaccinated were 3.6 times more likely to get COVID-19 and 23 times more likely to be hospitalized compared to people who were vaccinated and boosted.

The unvaccinated were 2 times more likely to get COVID-19 and 5.3 times more likely to be hospitalized compared to people who were vaccinated but not yet boosted, according to the study, which was published in the CDC's weekly journal, MMWR.

-ABC News' Sony Salzman