NEJM: Testing Undermining Pandemic Response

2,703 Views | 11 Replies | Last: 3 yr ago by PJYoung
Jmiller
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May 15, 2020
DOI: 10.1056/NEJMp2014836
Quote:

Tragically, the United States, unable to match other countries' response, has tallied the most cases and deaths in the world and recent data suggest that those tallies are underestimates. Why has the U.S. response been so ineffectual? One key answer is testing, which has been a cornerstone of Covid-19 control elsewhere. U.S. testing to identify people infected with SARS-CoV-2 has been slow to start and to this day has not sufficiently ramped up. Testing was delayed in January and February as the Centers for Disease Control and Prevention (CDC) distributed faulty test kits, then failed to approve a working test developed by the World Health Organization or those developed by local public health laboratories. Since March, the number of tests per day has never reached the number needed because of shortages of reagents, materials, and personal protective equipment (see graph).
Quote:

To date, efforts to bolster testing have focused on operational issues: whether testing capacity is adequate, why shortages and supply chain failures are so pervasive, and how to scale up testing to the massive numbers needed to mitigate the U.S. epidemic. Yet offering more tests is not a strategy in and of itself. If enough tests were available, we would still need to answer a fundamental question: What decisions are the results meant to inform? Testing has many purposes beyond diagnosis and protection of health care workers. Testing data are needed to manage all aspects of a pandemic. For instance, they are a cornerstone of epidemic forecasting models, which are sorely needed to reveal the future demand for care, including the timing of case surges and the magnitude of required emergency medical services, hospital staff, hospital beds, ventilator equipment, and mortuary services. Without good testing data, forecasters have to rely on guesswork and assumptions.
Quote:

That the United States is failing such a simple test of its capacity to protect public health is shocking. Collecting and reporting public health data are not rocket science. Other countries, notably Canada and Belgium, are already reporting nationwide data on testing at the individual level, including individual demographic data (using ranges for each person to protect privacy) and other key attributes for each test.4 The United States was once a leader in collecting systematic federal data on population health. Now our national disease-tracking effort seems stuck with well-meaning but scattershot efforts by tech companies using cellular phone signals, social media surveys, online searches, and smart thermometers as we try to guess where Covid-19 outbreaks may be lurking. Small one-off studies using convenience samples have popped up to try to fill the vacuum with basics such as percentages of cases that are asymptomatic and of symptomatic people who seek care. Because of sampling bias, these studies are producing wildly different and nearly uninterpretable results. Estimates are so wide ranging that modelers have little choice but to default back to imprecise assumptions.
Quote:

In the information age, the United States seems to be swimming in big data. This country has generated many of the world's largest, most innovative, most profitable data companies. Yet when it comes to forecasting the spread of a major pandemic that is killing Americans and wreaking havoc on our economy, we seem oddly lost. With more than 80,000 dead and no end in sight, our national efforts seem feebler and more halting than the 19th-century work of Florence Nightingale in the Crimean War and William Farr in England, where they used systematically collected epidemiologic data and rigorous analysis to save countless lives. Would that our statistical models had such standardized, systematically collected, and readily reported data to inform them. Reopening state economies without the precision provided by analysis of rigorously reported testing data seems a peculiarly American form of madness.
Rachel 98
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AG
My understanding is that most of the testing centers have been complaining about not enough people coming in to be tested at this point. I understand that initially there were not enough tests, reagents, etc. but since then I have read multiple articles stating that testing centers are lacking for customers. It's hard to see how we could increase the numbers of tests without mandating testing, which maybe this author would support?
GAC06
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AG
Weird, our tests per million population are on par with other developed countries despite having significantly lower deaths per million.
Ranger222
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AG
Not surprised to see such a juvenile retort to a relevant issue on this forum that not only is allowed, but also sadly accepted here.

With little/no federal guidance on testing, states have been left to fend for themselves in terms of how tests are administered, counted and routing of supplies to complete the tests. That caused the underperformance at the beginning of this pandemic, with only a ramp up in the last couple of weeks.

As the author states, there is no national databank for us to view the data, and being able to understand and draw conclusions from it. It leaves us bickering about data from other countries for us to set policy and guidelines here. Additionally, while some states have excelled in their data acquisition and response, other states put out confusing and non-trustworthy data. Even Texas has issues, as they were reporting until last week combined PCR and antibody tests as one statistic.

Quote:

After facing questions about the accuracy of state figures on coronavirus testing, health officials in Texas have changed how they report data about the number of standard tests for the virus and antibody tests that have been administered.

Until Thursday, the Texas Department of State Health Services combined the count for antibody tests with the count for standard viral tests to produce a tally for the total number of tests administered.

On Tuesday, the agency told the American-Statesman Editorial Board that it would start separating the numbers moving forward, but the agency would not update earlier figures.

The tally for total tests administered in the state has been used by Gov. Greg Abbott and other officials to calculate the positivity rate of the virus in Texas, or the ratio of positive coronavirus cases to the total number of tests administered.

But antibody tests, which are used to determine whether an individual was previously infected with the coronavirus, are different from standard virus tests, which assess whether a person is currently infected.

https://www.statesman.com/news/20200522/texas-stops-combining-coronavirus-antibody-viral-test-data

And with a lack of testing comes little to no desire for contract tracing, which is a crucial element for many companies to control infection numbers.

For a country that wants to jumpstart the economy quickly, it is not providing the tools to do so. The economy will only recover when the consumer is confident to return. We are not optimally doing that with our current practices.
fightingfarmer09
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Ranger222 said:

Not surprised to see such a juvenile retort to a relevant issue on this forum that not only is allowed, but also sadly accepted here.

With little/no federal guidance on testing, states have been left to fend for themselves in terms of how tests are administered, counted and routing of supplies to complete the tests. That caused the underperformance at the beginning of this pandemic, with only a ramp up in the last couple of weeks.

As the author states, there is no national databank for us to view the data, and being able to understand and draw conclusions from it. It leaves us bickering about data from other countries for us to set policy and guidelines here. Additionally, while some states have excelled in their data acquisition and response, other states put out confusing and non-trustworthy data. Even Texas has issues, as they were reporting until last week combined PCR and antibody tests as one statistic.


It's almost like we are a constitutional republic that grants unique powers to states to control of their required responses to problems, rather than a one size fits all nationwide approach.

Wild.
BiochemAg97
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AG
It amuses me to see the current media's obsession with combining the antibody and virus tests. They didn't care a couple of weeks ago when the positive antibody tests were increasing the daily new counts. But now, they care that they are combining negative test results.

A positive antibody test shows exposure at some point in the past, and could likely be an already recovered patient. Counting those in the new daily numbers clearly made those look worse.

A negative antibody test (assuming also tests for IgM) tells you they weren't infected a week ago. That is still useful information in understanding current case counts and actually creates a smaller error window than lumping in positive antibody tests in the new daily case count. Especially if you consider most people are getting tested because they have symptoms, which don't manifest for about a week, meaning the positive viral tests are identifying people who were infected a week ago.
Goose83
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AG
Would be nice if we were testing more, as we'd get a better grip on the actual mortality numbers, as well as an idea of how far along we might be towards establishing some sort of herd immunity.
Carnwellag2
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Goose61 said:

Would be nice if we were testing more, as we'd get a better grip on the actual mortality numbers, as well as an idea of how far along we might be towards establishing some sort of herd immunity.
this seems swell - but in the grand scheme of things - i don't see why that is important. The mortality rate will be interesting to read about in the text books, but doesn't effect anything.

Ranger222
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AG
I'm losing you on the point you are trying to make regarding timing and test taking. A person experiencing symptoms or recently experiencing symptoms should take a PCR test. I don't think anyone should be expected to take any type of antibody test while infected, especially since we are still unclear on how long a person can shed infectious viral particles and you are dealing with bodily fluids to take an antibody test. It does not seem like a good idea to be using IgM to indicate active infection, especially when a lot of these serology tests still have issues with sensitivity and cross-reactivity to other coronaviruses and only a handful, such as Roche ELISA, meeting the necessary standards.

The problem with combining PCR + serology tests in one figure is you may give the false perception that PCR testing capacity is increasing when it is not. Many states were showing increasing in testing which I thought was a good sign, but instead they are not increasing their capacities like the data should show, instead they are just adding a different, completely separate test that causes an increase in total testing numbers. This also counts people twice if they have received a PCR test at one point and then a serology test later. Its not exactly the effect you would hope that data should show.

We want to get people back out in community, but we must continue to increase our surveillance and testing efforts to make sure we are keeping infection rates low so that we can have a functioning economy and society. A couple slip-ups, like this example, will strain our resources and lead to new outbreaks. Just because we are getting back out doesn't mean we should be holding at a steady-state. We need to be still increasing our efforts and properly managing the data:

Quote:

Two hairstylists who tested positive for COVID-19 may have exposed 140 customers to the virus.

The stylists worked at the same Great Clips salon location in Springfield, Missouri.

"This scenario is well within our capacity of our staff to contact trace and hopefully contain," Clay Goddard, Springfield-Greene County Health Department director, said in a news conference. "But I'm going to be honest with you, we can't have many more of these. We can't make this a regular habit or our capability as a community will be strained and we will have to reevaluate what things look like going forward."

https://www.wsbtv.com/news/trending/coronavirus-two-hairstylists-expose-140-clients-covid-19/EPUKPN7XDNCELGTB7RJO5TTPK4/
BiochemAg97
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AG
Yes, if you have symptoms you should take the PCR test. I'm not suggesting sick people take the antibody test.

My point was that a negative antibody test is also informative about the infectious state of the person not that long ago, and likely still a relevant timescale for epidemiology. If you have a random asymptomatic individual and you test for virus and it is negative, then you know they didn't have the virus yesterday, but it doesn't tell you they didn't get it at the test site. If you give them an antibody test and it comes back negative, then you know they didn't have the virus a week ago, but still don't know if they got it yesterday or today at the test site. The only difference is how far back they look. A negative result is clinically insignificant because it only tells you the past.

Positive results are significant. A positive virus test says they have the virus now. A positive antibody test tells you they had the virus in the past and will have antibodies going forward (at least for a period of time).

I think combining the test results is dumb and had issue with it weeks ago and was frustrated by reports suggesting they were combining the data. But the media seems to be focused on the problem with adding the two negatives together, ignoring the problems associated with adding the positive antibody tests in with the positive virus tests as new daily cases. And i haven't seen the media discuss of your (legitimate) concern that adding antibody tests to the total can mask a steady level instead of increasing virus testing.

It just seems that the media focus on the problem now and only the combining of negative results might be self serving and/or agenda driven. No one in the media had a problem when combining the results increased the new daily counts because then the story of things getting worse was intact. Now that numbers are decreasing in some states that have reopened, which is counter to the narrative, they seem to have gone looking for an explanation and found this one.
Detmersdislocatedshoulder
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Us total tests equal to that of Germany Russia and Great Britain combined.
Sisyphus
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The combined populations of Germany, UK and Russia are less than that of the US
PJYoung
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AG
Detmersdislocatedshoulder said:

Us total tests equal to that of Germany Russia and Great Britain combined.

Look at tests per positive infections.

We still lag.
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