In the hours after President Donald Trump and first lady Melania Trump tested positive for the novel coronavirus, members of their inner circle, the administration, and high-ranking Republicans in general seemed determined to comfort the public by announcing that they had tested negative for the deadly pathogen.
There’s just one problem: In all likelihood, it’s too soon to know that they haven’t been infected.
Most epidemiologists, public health experts, and studies suggest it takes days after exposure to the coronavirus before a test will provide an accurate picture of infection. And even then, nothing is a sure bet.
“You could generally assume that a test 48 hours after contact could be positive [if you are infected]” said Dr. Adrian Hyzler, the chief medical officer for Healix International, which provides medical information to organizations whose clients travel internationally. “However, it could take much longer.”
Attorney General Bill Barr, Treasury Secretary Steven Mnuchin, Vice President Mike Pence, White House Chief of Staff Mark Meadows, and Health and Human Services Secretary Alex Azar all announced on Friday that they had tested negative for the virus after being screened amid the news about the first family.
“Out of an abundance of caution I was tested for COVID-19 this morning and the result was negative. I will be testifying before Congress as scheduled,” Azar wrote on Twitter.
But Dr. Irwin Redlener, founding director of the National Center for Disaster Preparedness and a senior research scholar at Columbia University’s Earth Institute, said that Azar’s decision to testify in person was, at best, ill-advised.
"Given what’s going on, it’s hard to believe that Secretary Azar still wants to testify in person,” said Redlener, after Azar was photographed in a mask on Capitol Hill. “What kind of defiant arrogance is this?”
As most Americans know by now, newly infected patients can exhibit symptoms of COVID-19 anywhere from two to 14 days after exposure to the virus. But a test within 24 hours of close contact with Trump—or Melania, or former Trump aide Hope Hicks, who also tested positive for COVID-19—is more symbolic than clinically significant.
Dr. Frederick Southwick—a University of Florida professor of medicine, infectious disease specialist, and member of the Committee to Protect Medicare—put it bluntly, calling a test within 24 hours of exposure “not of benefit.”
The uncertainty here despite negative test results is perhaps best illustrated by a study on false-negative rates published last month in Annals of Internal Medicine. In the study, the probability of a false negative on a PCR, or diagnostic test—as opposed to a rapid test, which has been used at the White House, and may be even less accurate—dropped from 100 percent on the first day after exposure to 67 percent on the fourth day. That rate dropped again, to 20 percent, three days after symptom onset.
That’s not to say it isn’t a good idea for Trump’s posse to get screened right away.
“Anyone who has been exposed to COVID-19 should be tested immediately,” said Lawrence Gostin, director of the O’Neill Institute for National and Global Health Law at Georgetown University. But he added that tests are most reliable “once symptoms have started.”
Ultimately, experts say, anyone who may have been exposed to the president should be tested right away—and then retested. In the meantime, publicizing their initial negative test results amounts to little more than a note of hopefulness.
“Four to five days after exposure is most likely to yield a true positive or negative,” said Southwick.