By: Mark Glennon*
Just as highly important information on antibody testing has started to come in for other states, Governor J.B. Pritzker recently announced that he will de-prioritize that testing. He’s withholding results collected so far in Illinois. His full comments are reproduced below.
That’s opposite of what other states are doing and is a mistake.
Antibody tests, also called serology tests, are important because they indicate how much of the population had coronavirus, though they probably never knew, and are therefore likely to be immune for some time. That information is also a key variable heavily influencing projections about rate of future infections.
Many headlines from other states are starting to focus on antibody testing because surprising results are now coming in that may begin to inform their policy on the virus. The tests only became available in early April.
Getting particular attention are new numbers from New York and Florida, where very large parts of the population tested positive for antibodies.
One in five New Yorkers may have had Covid-19, the tests suggest, as reported by the New York Times on Thursday. Governor Andrew Cuomo said that might mean the death rate is far lower than believed.
Miami-Dade County test results also showed a surprisingly big part of the population with antibodies. About 6% — around 165,000 residents — have antibodies indicating a past infection by the novel coronavirus, dwarfing the state health department’s tally of about 10,600 cases, according to the Miami Herald on Thursday.
A recent Stanford University antibody study estimates that the fatality rate if infected is likely 0.1 to 0.2 percent, a risk far lower than previous World Health Organization estimates that were 20 to 30 times higher and that motivated isolation policies, as reported by The Hill.
Antibody testing started this month in Illinois with quite a bit of fanfare and publicity. The Chicago Tribune, for example, quoted a spokesman from Family First Medical Group saying, “The test we’re using … is the one most supported by the medical community, including researchers from Stanford…. We’re confident in its safety and results. Overall, they seem to be very accurate.”
What are those Illinois tests saying? That’s what Pritzker isn’t releasing.
But one indication may have come from the Chicago City Wire whose reporters visited Roseland Community Hospital on Chicago’s south side. It was among the first to begin offering serology tests and is doing hundreds of tests per day. A phlebotomy nurse there, according to their story, estimated that a stunning 30% to 50% of patients have been testing positive for antibodies. I emailed the hospital for comment but got no response.
Reliance on antibody testing by individuals has been challenged because the testing has a high error rate, producing many false positives in particular. The Federal Drug Administration has warned about those inaccuracies and said not to use the tests as a “sole” basis for diagnosis of the virus, although it recommends continued use of the tests. Some in Congress, too, are worried about people relying on inaccurate tests. However, some tests may be more accurate than others. Abbott Labs claims its test is 99% accurate. It has been approved for use in the European Union where millions of the tests are now being distributed.
But there’s a critical distinction here between an individual relying on the tests and the broader empirical value of what the tests indicate about general immunity levels. Dr. Scott Gottlieb, the former commissioner of the Food and Drug Administration has said just that. Given the frequency of false positives, nobody should think they are bulletproof if they get a positive test.
However, adjustments to reflect the error rates can be made for broader research purposes, and that’s the key. As stated in that Miami Herald article about the study there, “researchers used statistical methods to account for the limitations of the antibody test, which is known to generate some false positive results. The researchers say they are 95% certain that the true amount of infection lies between 4.4% and 7.9% of the population, with 6% representing the best estimate.”
Axios put it this way: “You can estimate the spread of a virus in a population with a serological survey (a.k.a. serosurvey), even with a less-than-perfect test. Then you can account for false results using statistical techniques in your analysis.”
Why wouldn’t Pritzker want this data or publish it? Maybe he thinks it’s his place to take it upon himself to protect individuals from their own misuse of the testing. On the other hand, if results here are consistent with New York, Florida, other states and what those Stanford researchers say, projections would undoubtedly be far rosier and Pritzker’s recent extension of stay-at-home rules would become more controversial. And Pritzker seems unconcerned about distinguishing the tests known to be inaccurate from those who claim to be accurate, such as Abbott Labs’.
I’d like to tell you to decide for yourself about how much to make of the new antibody test results for Illinois; I am not trying to make that call for you. But we can’t decide for ourselves because we don’t have the information. Pritzker won’t release the data and now he will cut back on the testing.
Illinois should be collecting and publishing antibody test results just as other states are.
Scrubbing hands is good. But scrubbing key data isn’t.
*Mark Glennon is founder of Wirepoints.
This article was updated on May 1, 2010.
Read more about the impact of COVID-19:
- COVID-19 pushes nation’s weakest pension plans closer to the brink: A 50-state survey
- Reopen the Economy While Protecting Those at Risk or Face Another Great Depression
- Illinois Senate Democrats Seek Massive Federal Bailout for State, Going Far Beyond Coronavirus Impact
- Here are the details on COVID-19 hospitalization numbers Illinois should have collected and published weeks ago
- The COVID-19 crisis: “If this goes on for another six weeks, we’d be destroyed.”
Comments by Governor Pritzker on antibody tests, April 24, 2020:
I also want to talk briefly today about antibody tests, which have been in the headlines recently and have created a lot of buzz. I want to make sure that people have the facts about whether and how these tests are useful.
In theory, these tests could be an effective tool. We’re craving answers in an uncertain time and antibody tests offer the potential for more security. But I’m afraid we’ve seen many of these tests promoted in a way that errs on the side of irresponsible.
To be clear, these tests are not quite where we need them to be to offer a true metric of immunity in Illinois. This is not an Illinois specific problem. As of today, there still are no antibody blood tests certifiably proven to accurately and consistently diagnose COVID-19 antibodies. There are several reasons for that.
First, no one yet knows the true sensitivity and specificity of these tests. That is how accurate or inaccurate they are. Obviously you want to test to be accurate and not offer many false positives or false negatives. That kind of accuracy is in part tied to how long it’s been since a person, potentially had the virus, since it takes, each of us time to produce antibodies, and it’s in part tied to the quality of the test.
Second, this is a novel virus, entirely new. So researchers don’t yet know the extent to which having COVID-19 antibodies equals, having immunity. That’s a question whose answers will only be revealed over weeks or months, and maybe even years, for example, is there a certain exposure level at which antibodies don’t protect you. Or, if you can become immune. How long would immunity last?
Third, it’s not yet confirmed that these tests are able to explicitly identify COVID-19 antibodies versus Corona viruses that cause things like the common cold. The test must, must definitively identify antibodies for COVID-19, and nothing else for them to be fully effective.
We’re monitoring those studies and we’re planning how we could deploy those tests when they’re ready. As soon as they prove themselves accurate and reliable, I will make it a priority to get them into our communities as widely as we can. What I won’t do is run full speed ahead with these tests before they’re proven. Because, among other things, we will be offering people a false sense of security. I’ve said since the beginning that here in Illinois, we will rely on factual data, and we will lead with the science. That, and the goodwill of the people of Illinois, will be what sees us through this pandemic.