WASHINGTON • Fighting the omicron variant surging through the country, President Joe Biden announced Tuesday that the government would provide 500 million free rapid tests, increase support for hospitals under strain and redouble vaccination and boosting efforts.

At the White House on Tuesday, Biden detailed major changes to his COVID-19 winter plan, his hand forced by the arrival of the fast-spreading variant, whose properties are not yet fully understood by scientists.

Yet his message was clear that the winter holidays could be close to normal for the vaccinated while potentially dangerous for the unvaccinated.

His pleas are not political, he emphasized. He noted that former President Donald Trump has gotten his booster shot, and he said it’s Americans’ “patriotic duty” to get vaccinated.

“It’s the only responsible thing to do,” the president said. “Omicron is serious and potentially deadly business for unvaccinated people.”

Biden chastised social media and people on cable TV who have made misleading statements to discourage people from getting vaccinated.

The outbreak from this latest strain of the coronavirus has required the federal government to get more aggressive in addressing the likely wave of infections, but Biden promised a weary nation that there would not be a mass lockdown of schools or businesses.

“I know you’re tired, and I know you’re frustrated. We all want this to be over. But we’re still in it,” Biden said. “We also have more tools than we had before. We’re ready, we’ll get through this.”

Scientists don’t yet know everything about omicron yet, but they do know that vaccination should offer strong protections against severe illness and death. The variant has spread at such an alarming rate that the Biden administration snapped quickly into action to offer new tests and additional aid.

A cornerstone of the plan is Biden’s decision for the government to purchase 500 million coronavirus rapid tests for free shipment to Americans starting in January. People will use a new website to order their tests, which will then be sent by U.S. mail at no charge, the White House said.

It marks a major shift for Biden, who earlier had called for many Americans to purchase the hard-to-find tests on their own and then seek reimbursement from their health insurance. For the first time, the U.S. government will send free COVID-19 tests directly to Americans, after more than a year of urging by public health experts.

Experts had criticized Biden’s initial buy-first, get-paid-later approach as unwieldy and warned that the U.S. would face another round of problems with testing at a critical time.

Testing advocates point to places like the U.K. and Germany, which have distributed billions of tests to the public and recommend people test themselves twice a week.

President Joe Biden speaks Tuesday about the COVID-19 response and vaccinations at the White House in Washington.

the associated press