Opinion: What President Trump and his aides repeatedly got wrong about coronavirus testing

Alpha Centauri is the closest star system to Earth. Even so, the starlight visible from here is more than 4 years old because of the distance it must travel.

So what does that have to do with the president’s coronavirus infection?

Coronavirus testing has to navigate a similar kind of delay. The tests aren’t that good at detecting whether we are infected if we’re tested within a couple of days of being exposed to the virus. That’s because it often takes more than a day or two for the virus to propagate in our bodies enough to be discovered. The tests are better at determining whether we were infected four or five days earlier — which is why health experts generally advise people to be tested five days after a possible exposure.

This tells us a lot about President Trump and the foolhardy way he has gone about his activities and his messaging on COVID-19. It’s true that the science about COVID-19 can be confusing and changes over time. But understanding it, and acting accordingly, are a literal matter of life and death. So why can’t our leaders get this right?

Trump is tested every day, with a rapid results test. So for each day he was tested, he knew that as of five or maybe seven days before, he hadn’t been infected. It’s a lot more information than most of us have. It lowers the chances that he has an infection, because at least he didn’t have one several days ago. But it is far from a free pass to attend a rally or social event — or, perhaps, an indoor debate with another elderly man in which there were no masks or plexiglass partitions. And the negative test results that former Vice President Joe Biden has gotten in recent days don’t mean he’s clear.

The issue isn’t just that Trump is sick; it’s how many people he might have exposed to all the president’s germs. And yet his administration continues to send out misleading and dangerous messages through irresponsible behavior.

White House Chief of Staff Mark Meadows wore no mask to talk to reporters Friday morning, using the pallid excuse that he’d gotten a negative test. A negative, you’d think he’d know by now, doesn’t necessarily mean he wasn’t infected. It just means any infection he might be carrying hasn’t gotten bad enough to be detected yet.

Likewise, if former Vice President Joe Biden was tested Friday, he still doesn’t know if Trump passed along the infection at the debate. That wasn’t long enough ago for a reliable negative result.

So what’s the point of testing? For people who are asymptomatic several days after being infected, it can tell them they are infected and must quarantine, though they should have limited their social interaction as soon as they knew they were exposed. And if the exposure was several days beforehand, a negative test lets them know they weren’t infected by it.

But if they haven’t been careful since that exposure and party like it’s 2019, they’re endangering themselves and the people around them. For months, Trump has been explicitly and implicitly giving the opposite impression. He has mocked masks and concerns about indoor spread and failed to physically distance himself. Will his latest bad news give him any new respect for science?

Well, there’s this much: The drug he pushed relentlessly for months, hydroxychloroquine, isn’t on his medication list.