- Testing has so far been used in the United States mostly for diagnostic purposes, which is when a test is used to determine or confirm what the problem is in people with symptoms.
- Screening, however, is meant for seemingly healthy individuals to look for signs of illness.
- Many public health specialists have repeatedly called on the CDC and other federal health officials to endorse and more aggressively pursue the strategies of surveillance testing and screening.
The Centers for Disease Control and Prevention is developing new guidance on how to deploy coronavirus tests for screening purposes that could help reopen schools, businesses and entertainment venues, Director Dr. Robert Redfield said Wednesday.
Testing has so far been used in the United States mostly to diagnose people who are sick or have been exposed to someone with a confirmed Covid-19 case. Screening would test virtually everyone in a given community, looking for potentially infectious people.
"Screening can be very powerful for maybe non-public health reasons, maybe getting us back to life, and screening in schools, K-12 screening and university screening," he said at a Senate appropriations subcommittee hearing. "We'll be coming out with some guidance around screening."
Redfield said the CDC would make it clear that testing asymptomatic and pre-symptomatic people — Covid-19 patients who either never develop symptoms or who are in the early stage of the infection before symptoms start — is important. The agency will have that guidance out within the week, he said. It's also working on new guidance around surveillance testing "where you can actually systematically begin to look at random individuals to get an idea is this outbreak starting to pop into the community," he said.
Redfield said the agency will eventually roll out guidance for how states and local health officials can best deploy resources to implement all three testing strategies.
Many public health specialists have repeatedly called on the CDC and health officials throughout the federal government to endorse and more aggressively use surveillance testing and screening. Redfield said Wednesday that the technology didn't allow for that kind of widespread testing before.
"It really wasn't possible to really have a lot of that guidance when there was no test," he said, adding that due to recent advances in Covid-19 testing technology, the nation is approaching a point where such methods can be used. "We're going to try to give guidance to screening, particularly in K-12s and universities, but it's also going to have a role in businesses, and also entertainment activity, like sports."
The new guidance will clarify the CDC's position on testing asymptomatic people, he said. Last month, the CDC revised its testing guidance to say that people who don't have symptoms "do not necessarily need a test."
Redfield said Wednesday that many people "misinterpreted" that wording and that the CDC was not suggesting people without symptoms should not be tested. He said the agency will continue to clarify its stance that more testing across the country will help detect the coronavirus and ultimately contain it.
Adm. Brett Giroir, an assistant secretary for health at the Department of Health and Human Services, said he agreed with Redfield's sentiment on the importance of screening and surveillance testing. He specifically mentioned Abbott Labs' BinaxNOW test, which is an antigen test that's inexpensive and can provide results in minutes. It was authorized by the Food and Drug Administration last month, and the U.S. government secured essentially all available tests through the end of the year.
Giroir, who is in charge of the Trump administration's testing efforts, added that other rapid and inexpensive tests could be coming to market in the weeks and months ahead. Such tests, he said, could be "layered on top" of the BinaxNOW test.
"Our goal is to provide as many tools as possible in the right domain. So we can implement this type of guidance," he said. "In March, it didn't make sense to talk about random screening of children going to school, because you didn't have that available."
He added that now the U.S. has a "very robust ecosystem" of testing and it "is the exact right time" to be considering screening and surveillance testing. Giroir previously said the federal government is distributing the 150 million BinaxNOW tests secured by the U.S. to states for them to determine how best to deploy them. However, Giroir added that he strongly encourages governors and state health officials to use the tests to protect their most vulnerable residents in nursing homes and then to help reopen schools.
"Within a couple of weeks, they're going out to states to support school reopening and other infrastructure, according to their priorities," he said of the tests. "We are at that point. We are at that inflection."