Coronavirus testing is key, but experts say a testing-only strategy is a 'complete failure'

The President was rarely seen engaging in two of the most effective and widely promoted public health measures, social distancing and wearing a mask, and many of those who surround him followed his lead.

For example, during the recent presidential debate in Cleveland, Trump not only mocked his Democratic rival Joe Biden for wearing a mask, his wife and grown children removed their masks after they were seated in the auditorium, in violation of the events rules.

Testing, however, was apparently a strategy Trump could get behind, and so he and his staff were tested often -- the President was said to be tested as often as once a day, possibly more, according to initial reports.

But Trump himself admitted earlier this summer he wasn't tested every day. And the White House has not said publicly when the last time the President tested negative before he developed symptoms and tested positive Thursday night.

Testing-only strategy a 'complete failure'

Unlike mask-wearing, testing would not "send the wrong message" as Trump has said in the past, and one he reinforced when he pointedly took off his mask on the White House balcony after leaving Walter Reed National Military Medical Center Monday night.

In light of recent developments -- the President, the first lady and an ever-widening circle of White House staffers and associates becoming infected with the coronavirus -- it's fair to say the testing-only strategy did not work out well.

That outcome does not surprise public health experts.

"It's a complete failure. It was just a matter of time," said Dr. Rob Murphy, a professor of infectious diseases at Northwestern University and executive director of the Institute for Global Health.

"They've been playing Russian roulette all this time, and they got away with it, considering how [many] interactions they have with other people, how close they are with everybody, how they don't socially distance and how they rarely ever wear masks. They got away with it for pretty long, but it's not enough," said Murphy.

Dr. Jared Baeten, the vice dean of the University of Washington School of Public Health and a professor of global health, medicine and epidemiology, agreed.

Testing the President every day "doesn't keep him any safer," said Baeten, but it did allow doctors to start therapies on him quickly.

"Testing is incredibly important but testing alone is not enough," he said. "Testing yourself every day only lets you know early ... really quickly after you've become infected. It doesn't prevent you from becoming infected."

Baeten said the purpose of testing, while very important, is not for preventing infection. It's about containing infection, so it's not transmitted to anybody else.

In theory, frequent testing among the President and his staff should have allowed Trump's infection to be caught early and contained, before he could potentially infect others.

But again, the testing-only strategy failed.

Thursday, before it was revealed Trump was infected, he flew to a private fundraiser in Bedminster, New Jersey, where all 206 attendees and the 19 staff members who worked the event, have now been asked to quarantine and are having their contacts traced.

The New Jersey fundraiser occurred on the heels of a Wednesday night rally in Minnesota, during which Trump's close adviser Hope Hicks started to feel sick. On the flight back to Washington with the President and other staffers, Hicks said she self-isolated. She later tested positive for the virus.

About the President's trip to Bedminster, New Jersey, Gov. Phil Murphy said, "It is clear that the President and his staff acted recklessly in the first place knowing they had been exposed to someone with a confirmed positive test."

Three ways in which testing-only can fail

Northwestern's Murphy outlined three basic ways testing can fail.

"Number one, the tests are not perfect. In other words, you could have false negatives," he said. That's especially true of the rapid antigen tests when used in asymptomatic people, which is how they are used at the White House, to screen visitors and staffers.

There are two kinds of diagnostic tests for the coronavirus: the PCR test, which looks for the virus' genetic material, and the antigen test, which looks for pieces of protein from the virus. (Diagnostic tests, which look for active infection, should not be confused with antibody tests, which can tell you if you have had a past infection.)

"Polymerase chain reaction testing -- that's still the gold standard. It is a comparatively expensive test to run. We still cannot get enough reagents [for it]," said Dr. Patrick Godbey, the president of the College of American Pathologists. Reagents are chemicals needed to run the tests. He said at times they can't get enough "consumables" either, such as nasal swabs.

"Antigen testing has advantages and it is cheaper. It requires much less instrumentation -- some antigen tests, none at all. Antigen tests tend to be very specific, but not very sensitive, particularly in asymptomatic people," he explained.

That means the tests might not pick up all the positive cases, returning instead a false negative, which is especially true in people not showing symptoms. But he added that the antigen tests are "fairly sensitive" when used in people within five to seven days of developing symptoms.

Early in the pandemic, the White House used an early version of a test from Abbott called ID NOW, which at the time was criticized for being less accurate than other available tests at identifying infected people. The White House reportedly switched a little over a month ago to Abbott's newer rapid test, BinaxNOW, which received emergency use authorization in August.

These tests were given EUA for use in people "within the first seven days of the onset of symptoms."

Said Murphy, "So, the test is not perfect; you can have false negatives, especially in the asymptomatics."

The second reason a test-only strategy can fail is that people don't test positive immediately after getting infected -- not even with the gold standard PCR test -- because it takes a while for the virus to replicate in a person's body to levels high enough to be picked up by a test. In fact, doctors recommend waiting at least five days after a suspected infection before getting tested.

"The viral level starts from zero and goes up," said Murphy. "You can be negative now and, at some particular point, you turn positive."

So there can be a lag time between getting infected and then testing positive, where even someone who gets tested every day, like the President and his staff, can be infectious, said Murphy, "because the person could be in the process of converting."

A third way a testing-only strategy can fail is what Murphy calls "system failure."

"They have the plan, but is everybody really getting [tested] every day?" Murphy wondered. "Did Hope Hicks -- I am just using her as an example --really have a test every day? Did any of them have a test every day? Did the President even have a test every day? Notice that they're not saying the last time he had a negative test."

This type of system failure appears to be at the crux of the coronavirus outbreak at the White House.

And it's also likely what turned the late-September Rose Garden ceremony, held in honor of US Supreme Court nominee Amy Coney Barrett, into a super spreader event. It was attended by many people who later became infected, including the President, first lady and Hicks. "When you have as many moving parts as they have, when you look at the number of people in the Rose Garden, look at the number of people at these events ... They're going to screw up, and it's just, it's just a matter of time before they just logistically make a couple errors."

Under systems failure Murphy adds a sub-category: personal failure -- where someone is "willing to ignore data" or just doesn't do what they should do. "In other words, you're told ... you were around somebody, you should quarantine -- and they don't bother. That's not system failure. That's a personal failure ... You knew you shouldn't have done it but you did it anyway."

Couple testing with other measures

Murphy said testing is a very good strategy to get infected people "out of circulation" very quickly. "However, you do have to do the social distancing and mask wearing. They go hand in hand; you can't just have one really without the other," he said.

Baeten also said testing every day, if it's not paired with other public health measures, can lead to a false sense of security and a whole lot of new infections.

"That's what breaks down and that's what broke down in the White House strategy: the virus gets ahead of the tests, and if you're not having prevention strategies in place to keep people who aren't infected [safe], you can't get completely ahead of that with testing alone," Baeten said.

As Trump's own testing czar, Adm. Brett Giroir, has said repeatedly "We can't test our way out of this."