Just as a summer COVID wave shows signs of receding, the Biden administration announced Wednesday that it is reviving a program to mail free rapid coronavirus tests to Americans.

Starting Sept. 25, people can request four free tests per household through covidtests.gov. Officials say the tests are able to detect the latest variants and are intended to be used through the end of the year.

The return of the free testing program comes after Americans navigated the latest uptick in COVID cases with free testing no longer widely available. The largest insurance companies stopped reimbursing the costs of retail at-home testing once the requirement to do so ended with the public health emergency in May. The Biden administration stopped mailing free tests in June.

The Department of Health and Human Services also announced Wednesday that it was awarding $600 million to a dozen coronavirus test manufacturers. Agency officials said the funding would improve domestic manufacturing capacity and provide the federal government with 200 million over-the-counter tests to use in the future.

“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,” HHS Secretary Xavier Becerra said in a statement.

Experts say free coronavirus testing proved to be an effective public health tool, allowing people to check their status before attending large gatherings or spending time with older or medically vulnerable people at risk of severe disease even after being vaccinated. It also enables people to start antiviral treatments in the early days of infection to prevent severe disease.

Federal officials say they mailed 755 million free tests in the first four rounds of giveaways. But more recently, Americans accustomed to free tests had to decide whether it was worth spending roughly $10 to $15 per test to verify whether every sniffle or cough was COVID or to follow Centers for Disease Control and Prevention guidance on when to end masking after infection.

The return of free tests might be too late to blunt the summer wave.

While coronavirus surveillance has been drastically curtailed, available metrics suggest the virus has peaked. Weekly hospital admissions have been rising since July and surpassed 20,000 in the week of Sept. 9, but the rate of increase is slowing. That same week, the percentage of emergency room visits involving the coronavirus declined for the first time since July. The presence of the virus in wastewater has declined in the Southeast and is plateauing in other parts of the country, according to the firm Biobot Analytics.

An HHS spokesman did not immediately return a request for comment on why the administration did not restart the program earlier as COVID infections were climbing.

Gregg Gonsalves, an associate professor of epidemiology at the Yale School of Public Health who has frequently criticized the Biden administration’s handling of the coronavirus, said the return of free testing is a “welcome development.”

“The first thing in public health is to know your status,” Gonsalves said. “We only have tools if we have the resources to access them, and many people don’t have the ability to go to buy a pack of tests when they cost $25 or $20 to get at the pharmacy.”

The next batch of free tests could come in handy ahead of a respiratory virus season when RSV and influenza are also circulating. Coronavirus cases and hospitalizations have risen every winter since the pandemic started as people gather indoors because of cold weather and to celebrate holidays.

Officials have stressed vaccination as the best way for Americans to protect themselves against severe COVID illness. An updated coronavirus vaccine targeting the latest versions of the virus, recommended last week by the CDC, is now available at some pharmacies and doctor’s offices.