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Medicine United States

Screening Travelers For Symptoms of COVID-19 Was Ineffective, CDC Study Says 88

Temperature and symptom-based screening programs don't help catch coronavirus cases, the US Centers for Disease Control and Prevention said in a new report that took a closer look at the programs used at US airports until mid-September. CNN reports: The CDC said this was a resource-intensive program that had a low case detection rate. Between January 17 and September 13, the CDC screened more than 766,000 travelers. Nearly 300 met the criteria for public health assessment, 35 were tested for the coronavirus, and nine tested positive. That means the program identified about one case per 85,000 travelers screened, the CDC reported Thursday in the agency's weekly report. This style of screening doesn't seem to work for a few reasons. Covid-19 has a wide range of nonspecific symptoms common to other infections, there are a high number of asymptomatic cases, travelers may deny symptoms or take steps to avoid detection and passenger data was limited.

The CDC also only shared contact information with local health departments for 68% of the passengers it screened. There were data collection problems, the report said, and some states opted out of receiving the information. The CDC ended the program September 14. Instead, the CDC has concentrated on communicating more with travelers to promote recommended preventive measures. The agency has also enhanced the public health response capacity at ports of entry. The CDC said travelers and their local communities would be better protected if there was "more efficient" collection of contact information for international air passengers before they arrive and real-time data that could be sent to US health departments. Pre-departure testing within 72 hours before the trip and testing upon arrival would help, as would rules that would encourage a traveler to self-isolate for a certain period.
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Screening Travelers For Symptoms of COVID-19 Was Ineffective, CDC Study Says

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  • by OMBad ( 6965950 ) on Thursday November 12, 2020 @10:08PM (#60718120)
    The obvious conclusion is that the CDC airport screening cures COVID-19. Just like the TSA screenings stopped terrorism.
  • The worst news is that testing 72 hours before a flight still results in cases passing through roughly in-line with cases in the population. 18:15,000 per Hawaii’s follow-up random testing program.
  • That's a big "duh" (Score:5, Insightful)

    by dgatwood ( 11270 ) on Thursday November 12, 2020 @10:34PM (#60718176) Homepage Journal

    Although I didn't realize quite how useless it would be (only a little over half of all COVID-19-positive people even have a fever), it was always a colossal waste of resources to do screening in any form other than rapid testing en masse.

    A far better approach is quarantine. If you have people coming in from a country that has a lot of cases, require them to quarantine themselves for two weeks before interacting with the general public. Or heck, do it regardless of what country they're traveling from.

    And of course, none of it is useful as long as we have an obscene number of active cases here in the U.S.; they're only really useful to keep us from getting new cases after we get our own house in order.

    • by Darinbob ( 1142669 ) on Thursday November 12, 2020 @11:29PM (#60718316)

      That's why Trumps China travel ban was ineffective, even though people praise him for it. It allowed people into the country who were US citizens and resident *without* quarantine. As if he thought only foreigners could catch it? Or he was scared to impose restrictions on Americans? It's just odd to brag about such a half assed plan. Yes, he did it before most european countries but that's no reason to brag that you screwed up. Yes, not everyone understood everything about the virus, but once we did learn more Trump did nothing and took no leadership.

      • A country cannot legally stop its own citizens from returning.
        • by Anonymous Coward
          New Zealand and China both quarantine all arrivals, including their own citizens. Maybe there's something special about the United States stopping them from doing the same, but clearly other countries are capable of doing it, and it's not just a "China is a dictatorship" thing.
        • A country can quarantine them. Even the US allows quarantines.
          In actuality, the "ban" let most people in who wanted to come in, it didn't do much. It was all show and no action.

      • That's why Trumps China travel ban was ineffective,

        There was no ban. No a single flight was stopped from landing [washingtontimes.com].

        even though people praise him for it.

        When facts don't matter, sure.

    • Looking at how inaccurate the readings from IR skin thermometers are when used at home, I really wonder how they can be used anywhere, particularly in mixed context like airports.

      Anyway, I now wonder if a better strategy wouldn't have been to let the least affected age range (5~17, but let's raise that to say 12 to 25) get it and build an immunity right at the start. Say you lock them down in their schools for 2 weeks, bring in an infected person in the middle, distribute mattresses and food (and condoms

      • by djinn6 ( 1868030 )

        I'd love to see the lawsuits from this. Just because it's unlikely to kill them, when you throw the virus at 30 million children, you'll have a lot of dead ones at the end. There also seem to be some fairly serious after effects on those who survive. It's one thing when they get it on their own. It's another when you're the one deliberately infecting them.

        Plus you have no right to take them from their parents without consent. The 5th Amendment says "no person shall... be deprived of life, liberty, or proper

        • by dargaud ( 518470 )
          If you promise 2 weeks of partying, you'd get a lot of volunteers... But I agree, it shouldn't be forced.
    • Although I didn't realize quite how useless it would be (only a little over half of all COVID-19-positive people even have a fever), it was always a colossal waste of resources to do screening in any form other than rapid testing en masse.

      You saw how great rapid testing worked out at Trump conventions, right? Everyone tested negative, so fe (if any) wore masks and maintained proper physical distance. Hey, everyone tested negative, so why put up with these inconveniences? Obviously there were false negatives and dozens of cases can be traced back to these conventions.

      A far better approach is quarantine. If you have people coming in from a country that has a lot of cases, require them to quarantine themselves for two weeks before interacting with the general public. Or heck, do it regardless of what country they're traveling from.

      Hawaii forced a 2 week quarantine on all visitors - even visiting from a neighbor island! Anyone caught breaking quarantine was fined and faced jail time. Not quite the face of

      • by dgatwood ( 11270 )

        Although I didn't realize quite how useless it would be (only a little over half of all COVID-19-positive people even have a fever), it was always a colossal waste of resources to do screening in any form other than rapid testing en masse.

        You saw how great rapid testing worked out at Trump conventions, right? Everyone tested negative, so fe (if any) wore masks and maintained proper physical distance. Hey, everyone tested negative, so why put up with these inconveniences? Obviously there were false negatives and dozens of cases can be traced back to these conventions.

        Just to be clear, I'm not saying that rapid testing will eliminate infections. But getting even 80-odd percent of COVID-positive people to stop spreading it would reduce the rate of infection by 80%, which if we could do it quickly enough and broadly enough, could be enough to push the R0 below 1.

        A far better approach is quarantine. If you have people coming in from a country that has a lot of cases, require them to quarantine themselves for two weeks before interacting with the general public. Or heck, do it regardless of what country they're traveling from.

        Hawaii forced a 2 week quarantine on all visitors - even visiting from a neighbor island! Anyone caught breaking quarantine was fined and faced jail time. Not quite the face of the Aloha Spirit Hawaii is known for, but they are controlling their numbers better than most of the mainland.

        Yeah, I have some friends who are over there now. New Zealand did the same thing, and maybe some others.

        And of course, none of it is useful as long as we have an obscene number of active cases here in the U.S.; they're only really useful to keep us from getting new cases after we get our own house in order.

        When your boat has a leak and is taking on water, you first patch the leak then bail water - or do both at the same time. As long as there's a hole, more water will get into the boat. This is the same analogy I used for illegal immigrants, too (cut of new illegal immigrants, then do something with the 16+ million already here). This approach is doubly important for commutable diseases. The number of new cases is already out of control without letting in new (potentially) infected people.

        Right now, it's more like patching the pinhole leak at the bottom while leaving the doors open with giant wa

  • Early on, we were told that you could be spewing infectious droplets 4 days prior to onset of symptoms, including a fever. And that's if you're symptomatic. And recently we've been told that some people can be infectious weeks or months after exposure, sometimes without symptoms.

    If testing isn't giving results instantaneously, even a 72-hour self-quarantine is going to "fix" the problem.

    And if I have to quarantine for 3 days before a flight, I can damn well DRIVE where I need to be, while "maintaining quara

    • <Cough, cough> [mit.edu].

    • by dgatwood ( 11270 )

      Early on, we were told that you could be spewing infectious droplets 4 days prior to onset of symptoms, including a fever. And that's if you're symptomatic. And recently we've been told that some people can be infectious weeks or months after exposure, sometimes without symptoms.

      If testing isn't giving results instantaneously, even a 72-hour self-quarantine is going to "fix" the problem.

      Correct. The median time to onset of symptoms is four days, so three days isn't even close to adequate. Two weeks of quarantine followed by a negative test would be adequate. Anything short of that is cutting corners, IMO, but two weeks without symptoms is probably good enough to catch at least 80% of cases (and probably a much higher percentage of cases that are shedding enough to matter).

      And if I have to quarantine for 3 days before a flight, I can damn well DRIVE where I need to be, while "maintaining quarantine"!

      I just drove most of the way across the country while coming darn close to maintaining quarantine. All motels, so y

      • I just drove most of the way across the country while coming darn close to maintaining quarantine. All motels, so you don't share air, airing out the room as much as possible before unmasking, checking in through night windows (all but one was entirely outdoors), going into stores only to use the restroom, bringing most of my food and drinks, taking all remaining food to go (and mostly via drive-through windows), etc.

        Try a travel trailer:
        - No motels. You brought your private bedroom, shower, and lo

        • Try a travel trailer: ...

          Most states allow you to park at rest areas for long enough for a good night's sleep. Drive on to the next one, or a roadside picnic table, for breakfast if they're being pedantic about not cooking in the trailer or "staying too long is forbidden camping".

          We have used one for years, to avoid allergy and cleanliness issues at motels when going cross-country. The plague year mitigations are more a matter of things getting extreme rather than qualitatively different.

          RVs are even more

  • by hambone142 ( 2551854 ) on Thursday November 12, 2020 @11:58PM (#60718374)

    Asymptomatic carriers don't have symptoms nor a fever.

    • Sometimes they do, it really depends. There's no medical standard for "symptomatic," and it varies from paper to paper. A lot of scientific papers rely on self-reporting of symptoms. The person may indeed have a fever, but if they don't notice it, they are asymptomatic.

      It's unfortunate, but that's the current state of the medical community. I suspect it's this way because that kind of reporting is good enough for doctors and the kinds of things they want to know, but it's not good enough for epidemiologis
      • by djinn6 ( 1868030 )

        What we know is more than good enough for epidemiologists. That is if they weren't working for governments that are actively trying to down play it the pandemic.

        If there's even a 5% chance that someone's symptom is undetectable via a thermometer, you'd have a 99% chance of not detecting an infected person for every 49 infected person you do detect. That means the only effective solution is to quarantine all of them and perform a conclusive virus test. No exceptions.

    • "Asymptomatic carriers don't have symptoms nor a fever." - Asymptomatic people are not sick. It is a false positive of the test.
  • by Canberra1 ( 3475749 ) on Friday November 13, 2020 @02:49AM (#60718680)
    Taiwan had better outcomes. Whatever the USA or CDC did, it was 3rd world standard, not best practice. Obviously those protecting their butts, will NOT be comparing reports, nor reporting what was not done well. May one suggest bulk spit/covid tests like China did when you know you are under 1%. Japan makes people wait. Clearly the USA was told 'Faster is better', so private healthcare could make a motza later. Box ticking and going through the motions theatre is a sure way to underperform.
    • "Whatever the USA or CDC did, it was 3rd world standard" - Nope. The Third World is doing much better than the USA. Look at the graphs for Egypt - pretty much nobody dies of it https://www.google.com/search?... [google.com] The reason is probably that the MMR and TB Vaccines provide significant protection against Covid19 also.
  • "Between January 17 and September 13, the CDC screened more than 766,000 travelers. Nearly 300 met the criteria for public health assessment [..]"

    This just in: people who feel sick, have a fever etc. are very reluctant to travel during a pandemic. More at 11.

    • This just in: people who feel sick, have a fever etc. are very reluctant to travel during a pandemic. More at 11.

      I'm not so sure about that. Especially when you know that you might be stuck far away from home for a long time due to upcoming travel restrictions, you will be motivated to reason that that chilly feeling is probably not Covid-19.

      • by neaorin ( 982388 )

        As the report states, fever above 100.4F [38C] was one of the criteria for health assessment. The fact that only 298 people even met that criteria suggests that most of them didn't show up at the airport, so the screening system acted as a deterrent in that regard. And no doubt some of them tried to conceal it by taking a Tylenol or something.

        But self-selection bias is clearly a factor here. It's a bit like saying that TSA failed to catch a single would-be hijacker after 9/11, ergo all the extra screening w

        • by djinn6 ( 1868030 )

          I think the conclusion they arrived at could be better worded as "temperature and symptom-based screening programs are insufficient to help catch coronavirus cases".

          The virus can't teleport across oceans, so regardless of method, someone must've brought it over and any screening the border agents performed is demonstrably inadequate. Moreover, given the second outbreak in Europe after reopening their borders, their screening is clearly inadequate too, and that is despite having many months of additional kno

  • What a shock, the Pandemic Theater show put on by the CDC in airports was just as effective as the Security Theater show put on by the TSA. I'm old enough to remember pre 9/11 air travel when you were asked "did you pack your own bags?" as a means of screening for terrorists. As if a terrorist is going to say "why no, my bomb-maker packed my bags. Drat! You've foiled my nefarious scheme!"

  • Controlling the spread of a disease that hardly ever has any serious symptoms is just very difficult. Most people will get it without noticing.
  • Temperature and symptom screening also struck out in this study of the highly controlled environment of Marine boot-camp induction.
    https://www.nejm.org/doi/full/... [nejm.org]

    At this point I'd like to see evidence that temp & symptom screening works and simply assume it does not until shown otherwise --JS
  • Why do you think countries which did get the virus under control have mandatory quarantine and testing requirements.

  • I always thought they needed to do screening spraying some air freshener and then asking people if they can smell it. Seems like this would catch at least some people as loss of sense of smell is a common symptom even when there are no others.
    • by ebvwfbw ( 864834 )

      I always thought they needed to do screening spraying some air freshener and then asking people if they can smell it. Seems like this would catch at least some people as loss of sense of smell is a common symptom even when there are no others.

      This is the government. It wouldn't be air freshener. It would be fart in a can. LOL.

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