TAMPA (WFLA/NBC) – President Joe Biden on Tuesday said even as the omicron COVID-19 variant spreads quickly across the U.S., Americans who are fully vaccinated can safely celebrate the holidays.

“We should all be concerned about omicron, but not panicked,” he said. “If you’re fully vaccinated, and especially if you got your booster shot, you are highly protected. And if you’re unvaccinated, you’re at a higher risk of getting severely ill from COVID-19, getting hospitalized, and dying.”

Biden said fully vaccinated people should “feel comfortable” celebrating the holidays as planned, but should continue wearing masks in some indoor settings.

“I know some Americans are wondering if you can safely celebrate the holidays with your family and friends,” he said. “The answer is yes you can, if you and those you celebrate with are vaccinated, particularly if you’ve gotten your booster shot.”

Biden specifically encouraged the unvaccinated to get their shots.

“It’s the only responsible thing to do,” the president said. “omicron is serious and potentially deadly business for unvaccinated people. Get vaccinated now. It’s free. It’s convenient. I promise you, it saves lives, and I honest to God believe it’s your patriotic duty,” Biden continued.

Scientists don’t know everything about omicron yet, but they do know that vaccination should offer strong protection against severe illness and death. The variant has spread at such an alarming rate since it was identified in South Africa about a month ago that the Biden administration snapped into action to offer new tests and additional aid. Still more is needed, some medical experts said.

Scientists say omicron spreads even more easily than other coronavirus strains, including delta. It accounted for nearly three-quarters of new U.S. infections last week.

The Associated Press contributed to this report.