CDC F's up again
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wrote on 22 May 2020, 19:42 last edited by
It's like the Stooges, but not as funny.
The Centers for Disease Control and Prevention is conflating the results of two different types of coronavirus tests, distorting several important metrics and providing the country with an inaccurate picture of the state of the pandemic. We’ve learned that the CDC is making, at best, a debilitating mistake: combining test results that diagnose current coronavirus infections with test results that measure whether someone has ever had the virus. The upshot is that the government’s disease-fighting agency is overstating the country’s ability to test people who are sick with COVID-19. The agency confirmed to The Atlantic on Wednesday that it is mixing the results of viral and antibody tests, even though the two tests reveal different information and are used for different reasons.
This is not merely a technical error. States have set quantitative guidelines for reopening their economies based on these flawed data points.
Several states—including Pennsylvania, the site of one of the country’s largest outbreaks, as well as Texas, Georgia, and Vermont—are blending the data in the same way. Virginia likewise mixed viral and antibody test results until last week, but it reversed course and the governor apologized for the practice after it was covered by the Richmond Times-Dispatch and The Atlantic. Maine similarly separated its data on Wednesday; Vermont authorities claimed they didn’t even know they were doing this.
The widespread use of the practice means that it remains difficult to know exactly how much the country’s ability to test people who are actively sick with COVID-19 has improved.
“You’ve got to be kidding me,” Ashish Jha, the K. T. Li Professor of Global Health at Harvard and the director of the Harvard Global Health Institute, told us when we described what the CDC was doing. “How could the CDC make that mistake? This is a mess.”
Viral tests, taken by nose swab or saliva sample, look for direct evidence of a coronavirus infection. They are considered the gold standard for diagnosing someone with COVID-19, the disease caused by the virus: State governments consider a positive viral test to be the only way to confirm a case of COVID-19. Antibody tests, by contrast, use blood samples to look for biological signals that a person has been exposed to the virus in the past.
A negative test result means something different for each test. If somebody tests negative on a viral test, a doctor can be relatively confident that they are not sick right now; if somebody tests negative on an antibody test, they have probably never been infected with or exposed to the coronavirus. (Or they may have been given a false result—antibody tests are notoriously less accurate on an individual level than viral tests.) The problem is that the CDC is clumping negative results from both tests together in its public reporting.
Mixing the two tests makes it much harder to understand the meaning of positive tests, and it clouds important information about the U.S. response to the pandemic, Jha said. “The viral testing is to understand how many people are getting infected, while antibody testing is like looking in the rearview mirror. The two tests are totally different signals,” he told us. By combining the two types of results, the CDC has made them both “uninterpretable,” he said.
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wrote on 22 May 2020, 19:53 last edited by
OK, a mistake
So what? So, they imply it could change reopening decisions.
But it doesn't say which way open/not open or how many or how long or who might be affected positively or negatively.
It was a "debilitating mistake". Who or what is debilitated?
Lots of drama, but I'm not sure why.
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wrote on 22 May 2020, 20:31 last edited by
This wouldnt have happened if Trump had acted sooner...,,
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wrote on 22 May 2020, 20:32 last edited by
So the idea is that you should have sufficient testing capacity in order to open up so that you can catch any new outbreaks and contain them.
The administrations plan I think listed specific testing capacities suggested for different phases of opening, e.g. 'be able to test all your healthcare workers with X frequency'.
SO that means you need to have a certain PCR (antigen test) capacity.
Adding your antibody test capacity in order to meet the milestone means you won't really meet it.