Infectious Disease Expert Says CDC Limits on Early Testing Likely ‘A Big Mistake’

A leading infectious disease expert said Monday that limitations on early testing for COVID-19 imposed by the Centers for Disease Control and Prevention was likely a “big mistake.”

Responding to a report in the New York Times that there may have been hidden outbreaks of the disease in New York, Chicago and other cities much earlier than previously thought, Dr. Emily Landon, associate professor of medicine and the executive medical director for infection prevention and control at UChicago Medicine, acknowledged the limitations of testing for the virus in the U.S. — especially early on.

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“I don’t think we did enough testing,” Landon said. “The testing limitations that the CDC had on who was allowed to be tested indicated that only people that met very, very specific requirements were able to be tested. And we automatically didn’t test anyone who had tested positive for the flu or any other respiratory virus and I think now, in retrospect, that might have been a big mistake.”

Over the weekend it was widely reported that the CDC had added six new symptoms associated with COVID-19. But Landon, who was tapped by Gov. J.B. Pritzker to help explain the importance of the stay-at-home order when he announced its initial rollout in March, said that adding new symptoms did not reflect new discoveries about the virus. She said most of the symptoms that were added would be expected with any flu-like disease.

“A lot of the symptoms that the CDC added are things that we’ve included in the symptom list from the very beginning,” Landon said. 

She noted that chills and shaking chills are really common for anyone with a fever, as are muscle aches. All of those symptoms were added to the CDC list.

Landon says the biggest issue in combating the virus is determining the role being played by people who have COVID-19 but aren’t experiencing any symptoms of it.

“That is the question of the century,” Landon said.

While it’s known that people who don't have any symptoms of the virus can in fact spread it to others, it’s unclear how long that may be the case.

“We know that people who are asymptomatic are definitely shedding some of the time,” Landon said. 

It’s also unclear if testing positive for the virus means you’re actively shedding it.

“A lot of people are making the assumption that a positive test means that you are shedding the virus or that you are infectious,” Landon said. “I’m not so sure that that’s the case. I’m also not sure that a negative test means that you are not shedding the virus.”

Landon notes that in both the early stages of the illness and during recovery the tests are not reliable and that patients may be “wavering” between positive and negative results.

At the moment, without more and better testing, including testing for antibodies, Landon said it's impossible to put a number on what percentage of people may be asymptomatic carriers of the virus.

“We don’t know,” Landon said. “Those virology tests (which test for antibodies) that you’ve been hearing a lot about will help us to understand how many people were asymptomatic but ended up having the disease but they are not going to be able to tell us how often they transmitted it to someone else and if that person had close contact or just casual contact. There’s still so much to learn and I think that’s one of the reasons why it’s really hard to decide how to get back into regular life. We just can’t tell who is infectious and who is not.”

Current antibody tests have at least two problems, says Landon. First, the tests haven’t yet been widely used and so it’s hard to determine just how reliable they are. Some of the tests may also react to other coronaviruses that cause the common cold.

“We certainly have tested some (antibody tests) in our lab that we don’t think are good at all,” Landon said.

But secondly, and perhaps more importantly, for those pinning their hopes on widespread testing for COVID-19 antibodies being the means to restart the economy, it’s not clear how much protection they may provide against getting the virus again. 

“We don’t really know whether having antibodies to this disease actually means you are immune,” Landon said. “That’s why none of us are really feeling like they are a great test.”

With video of a house party on the West Side circulating widely and drawing sharp criticism from Pritzker and Chicago Mayor Lori Lightfoot, Landon said that while she understood the stay-at-home order was unprecedented and perhaps difficult to comprehend, it remains the most effective way to reduce the spread of the virus and ease the burden on the health care system.

“We cannot even imagine what are society would be like if we let this run rampant through our communities,” Landon said. “I think it is really hard for people to understand that they have to keep behaving in a way that they don’t want to behave and they’ve never had to behave before in order to avoid something that they can’t imagine.” 

But she said it’s crucial to drive home the message to stay home as much as possible, and to follow social distancing guidelines and wear a mask when you must go out.

“I don’t know what it is going to take,” Landon said. “I hope what it doesn’t take is a horrible outbreak where hundreds of people can’t get the care they need because of parties like that one. It’s really irresponsible.”

And with a vaccine and new viral therapies possibly more than a year away, Landon said that we will likely to be battling this virus for a long time to come.

“if you are counting the case numbers for just this wave you might be able to say we are just past the middle of it — but that’s just for this wave. If we are talking about the overall pandemic, this is still the beginning,” she said.

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