"Unfortunately, it's possible, especially if you go into this school year without the kind of mitigation that we had in place last year," Gottlieb, the former FDA chief in the Trump administration, said on CNBC's "The News with Shepard Smith"
"We can't expect to have less measures implemented, in terms of trying to control the infection in schools, and expect the same result, in terms of keeping the infection at bay."
The American Academy of Pediatrics found that children accounted for 15% of all new Covid cases last week. Gottlieb recommended Covid mitigation tools for schools such as masking, keeping children in defined social pods, routine testing and retrofitting air filtration systems.
Gottlieb underscored to host Shepard Smith that schools should not take their "foot off the break" if the goal is to stay open.
"This is a much more contagious variant, it might be much more difficult to control this in the school, so the goal should be to keep schools open, and try to keep these measures in place until we see how it goes," said Gottlieb.
Disclosure: Scott Gottlieb is a CNBC contributor and is a member of the boards of Pfizer, genetic testing start-up Tempus, health-care tech company Aetion Inc. and biotech company Illumina. He also serves as co-chair of Norwegian Cruise Line Holdings' and Royal Caribbean's "Healthy Sail Panel."