A top official at the World Health Organization said Thursday that COVID-19 mutations will likely lead to a surge in cases this fall, prompting parts of the U.S. to bring back health guidelines. 

"I could foresee that in certain parts of the country, there could be a reintroduction of indoor mask mandates, distancing and occupancy limits," Lawrence Gostin, the director of WHO’s Collaborating Center on National and Global Health Law, said, according to CNBC.

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He continued, "We are heading for a very dangerous fall, with large swaths of the country still unvaccinated, a surging delta variant and people taking off their masks."

FAUCI: STOP WITH THE POLITICS AND GET THE SHOT

Pfizer is about to seek U.S. authorization for a third dose of its COVID-19 vaccine, saying that another shot within 12 months could dramatically boost immunity and maybe help ward off the latest coronavirus mutant.

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Research from multiple countries shows the Pfizer shot and other widely used COVID-19 vaccines offer strong protection against the highly contagious delta variant, which is spreading rapidly around the world and now accounts for most new U.S. infections

The Associated Press contributed to this report