The U.S. has performed more than 70 million Covid-19 tests, and is testing around 4.7 million per week, according to data from the Covid Tracking Project. That’s down from a peak of more than 5.7 million in late July.

But to contain the virus, the U.S. should be testing many more. Ashish Jha, head of the Harvard Global Health Institute, told NPR in June that it would take 1 million tests a day to contain it, 4.3 million to suppress it. But supply shortages and challenges getting results quickly have hamstrung efforts to test more Americans.

There's a tension in deciding who should be tested when supplies are limited. Screening people, including those who have no known exposures or risks, can spot carriers of the virus and prevent them from spreading it. But doing large-scale surveillance testing can exacerbate bottlenecks at labs, delaying diagnoses.

With about 1.2 million Americans living in nursing homes, testing weekly would take up a quarter of the current number of weekly tests being performed.

Premier Inc., a large purchasing group that works with hospitals, nursing homes, and other medical providers, recommends combining testing with other prevention strategies and is advocating for federal funding to help facilities install electronic systems to better keep track who may be at risk.

“Blind testing of all nursing home residents regardless of risk factors is likely a waste of resources,” said Soumi Saha, senior director of advocacy at Premier.

Pressure will likely increase as schools, colleges, and workplaces count on screening tests to bring people back safely, she said. “Scarce resources are only going to become worse as society returns to normal.”

Early on, the lack of widespread testing allowed the virus to spread invisibly, blindsiding health officials. Since then, the country has sharply increased production of tests as well as the supplies required to perform them. But doctors warn there still isn’t enough to do blanket surveillance.

Student Testing
So groups including the AMA urged the Trump administration this month to update guidelines “to ensure that the limited testing resources available are directed at those with a medically-indicated need for tests and those identified by well-defined public health surveillance efforts.” 

The CDC guidance shifted away from testing those who were in close contact with to a diagnosed case. But the AMA letter recommended that tests go first to people with symptoms, known exposures to Covid-19, or those who needed tests before medical procedures, citing the surge in demand from students, employees, and people seeking a clear test to travel.

“We simply do not have the resources to meet the huge demand for testing by asymptomatic individuals without exposure to Covid-19,” the AMA wrote.

Weekly testing of the nation’s 3.7 million teachers or 20 million college students would quickly outstrip capacity.

Yet some places are attempting to test at that pace. Undergraduates and grad students in Columbia University dorms, for example, will begin the semester with weekly surveillance testing, according to the university’s plan. The University of Illinois at Urbana-Champaign aims to screen twice a week with a new saliva-based test it developed.