WASHINGTON (AP) — The Biden administration announced Wednesday that it is providing $600 million in funding to produce new at-home COVID-19 tests and is restarting a website allowing Americans to again order up to four free tests per household — aiming to prevent possible shortages during a rise in coronavirus cases that has typically come during colder months.

The Department of Health and Human Services says orders can be placed at COVIDTests.gov starting Sept. 25, and that no-cost tests will be delivered for free by the United States Postal Service.

Twelve manufacturers that employ hundreds of people in seven states have been awarded funding and will produce 200 million over-the-counter tests to replenish federal stockpiles for government use, in addition to producing enough tests to meet demand for tests ordered online, the department said. Federal officials said that will help guard against supply chain issues that sparked some shortages of at-home COVID tests made overseas during past surges in coronavirus cases.

Dawn O’Connell, assistant secretary for preparedness and response at HHS, said the website will remain functional to receive orders through the holidays and “we reserve the right to keep it open even longer if we’re starting to see an increase in cases.”

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“If there is a demand for these tests, we want to make sure that they’re made available to the American people for free in this way,” O’Connell said. “But, at this point, our focus is getting through the holidays and making sure folks can take a test if they’re going to see Grandma for Thanksgiving.”

The tests are designed to detect COVID variants currently circulating, and are intended for use by the end of the year. But they will include instructions on how to verify extended expiration dates, the department said.

The initiative follows four previous rounds where federal officials and the U.S. Postal Service provided more than 755 million tests for free to homes nationwide.

It is also meant to complement ongoing federal efforts to provide free COVID tests to long-term care facilities, schools, low-income senior housing, uninsured individuals and underserved communities which are already distributing 4 million per week and have distributed 500 million tests to date, the department said.

O’Connell said manufacturers would be able to spread out the 200 million tests they will produce for federal use over 18 months. That means that, as demand for home tests rises via the website or at U.S. retailers when COVID cases increase around the country, producers can focus on meeting those orders — but that they will then have an additional outlet for the tests they produce during period when demand declines.

“We’ve seen every winter, as people move indoors into heated spaces, away from the outside that, over each of the seasons that COVID’s been a concern, that we have seen cases go up,” O’Connell said.

She added that also “there’s always an opportunity or chance for another variant to come” but “we’re not anticipating that.”

“That’s not why we’re doing this,” O’Connell said. “We’re doing this for the fall and winter season ahead and the potential for an increase in cases as a result.”

HHS Secretary Xavier Becerra said that the “Biden-Harris Administration, in partnership with domestic manufacturers, has made great strides in addressing vulnerabilities in the U.S. supply chain by reducing our reliance on overseas manufacturing.”

“These critical investments will strengthen our nation’s production levels of domestic at-home COVID-19 rapid tests and help mitigate the spread of the virus,” Becerra said in a statement.