The federal government will provide free COVID-19 tests by mail starting in late September, as it kicks off a fall campaign urging eligible Americans to get vaccinated against COVID, flu and RSV, health officials said today.

Households can order up to four free tests through COVIDTests.gov, officials from the U.S. Centers for Disease Control and Prevention and the Department of Health and Human Services said at a press briefing.

The popular free testing program has had several rounds since it started in January 2022.

This year, the government campaign is timed to the fall and winter seasons, when temperatures drop and people stay indoors more, Dawn O’Connell, assistant secretary for preparedness and response at the HHS said.

COVID has been on the rise this summer, with hospitalizations jumping from 1.1 per 100,000 people at the beginning of May, to 4.4 at the beginning of August. The number of deaths has also risen during that period.

Health officials said even though previous vaccines and infection provide some immunity, people should get the updated shots, approved on Thursday, and also test.

“The virus continues to change faster than the flu virus,” said U.S. CDC Director Mandy Cohen.

“The severity of COVID looks more similar to flu, but if you still put head-to-head… in terms of what is hospitalizing more folks and what is killing more folks, COVID is being (a) more dangerous virus than flu,” Cohen said.

She also said COVID was now endemic, but there were tools to protect people.

The U.S. Food and Drug Administration approved updated mRNA COVID vaccines on Thursday that target a recently circulating variant, in order to better protect the population heading into cold weather.

The updated vaccines include those made by Pfizer , its German partner BioNTech and Moderna . The FDA did not clear Novavax’s traditional protein-based shot and is still reviewing it.