The head of the country’s second largest teachers union called for COVID-19 vaccines to be mandated for all students in public schools, with the Omicron variant rapidly taking hold across the country.

In an interview with Yahoo Finance Live, American Federation of Teachers (AFT) President Randi Weingarten said the protection vaccines offered against the highly infectious variant acted as a "silver lining" for schools grappling with yet another winter surge, two years into the pandemic.

“If we know that vaccines are the single most important way of keeping people safe, keeping our kids safe, keeping our kids in school, keeping educators safe, if we know that and we get by the day, more information about how safe they are, then that's a way that we need to move,” she said.

School districts across the country have already begun imposing mandates for eligible students, with the U.S. Food and Drug Administration (FDA) approving Pfizer-BioNTech’s two-shot COVID-19 vaccine for kids between 5- and 11-years-old in November.

California has moved most aggressively, announcing the state would add the COVID vaccine to the list of vaccinations required to attend school, once the doses receive full approval from the FDA.

Last week, the New Orleans School District expanded its mandate to include students age 5 and up, the first of its kind in the U.S. The vaccine mandate will go into effect on Feb. 1, even before Louisiana implements a statewide measure requiring all eligible students to receive the two-dose vaccine for the 2022-2023 school year.

“The only silver lining right now is that we know if vaccinated, they're not going to get really sick,” Weingarten said.

The debate over mandates is heating up as the Omicron variant fuels a new surge in infections across the U.S. Roughly 7.4 million children have tested positive for COVID-19 since the beginning of the pandemic, with case counts among the youngest patients increasing nearly 30% this month, according to data from American Academy of Pediatrics. Children accounted for nearly a quarter of all new cases, as of Dec. 16.

Yet, a recent poll by the Kaiser Family Foundation found that parents of 5- to 11-year-olds remain divided in their support for mandates. While more than a quarter said they are eager to get a vaccine for their child, more than half said they are worried their children may be required to get a vaccine even if they don’t support it. Hesitant parents highlighted the unknown long-term effects and serious side effects of the vaccine as a key concern.