The effort is the first attempt at formalizing a national testing strategy — something public-health experts have wanted for months. It comes amid a puzzling drop in the total number of tests recorded in the United States, from nearly 2 million a day in mid-January to about 1.5 million a day now. Public health experts attribute the decline to several factors, including widespread winter storms, increased reliance on point-of-care tests with results that are often not reported to health authorities and pandemic fatigue. The number of new cases is also declining, and the number of Americans who have been vaccinated is climbing.

But the widespread testing envisioned by the Biden program is sorely needed to help bring the pandemic to an end, experts said — even with three vaccines now available. A surveillance system that uses testing to track the spread of the virus and its variants can help communities determine how to safely reopen schools and offices, and eventually return to a more normal life.

“You need to be testing broadly even with the vaccine,” said Scott Becker, CEO of the Association of Public Health Laboratories. “We’re still going to want to make sure that we have a good handle on this pandemic. We want to watch that tail end.”