I see a lot of news about the desire to increase testing. What exactly is the intended goal of testing? Is it to identify people who have HAD the virus, and as such, are presumably safe to return to work? Or is it intended to identify people who CURRENTLY have the virus?
If the latter, are repeated re-tests anticipated? I mean, just because I don’t have it today, doesn’t mean I won’t have it tomorrow or next week.
Apologies if these are stupid questions, but I’m surprised that, despite the feet of space in my paper given to testing, they don’t address this basic sort of thing.
Huh, I’m surprised that it’s not covered in what you’re reading but both types you mentioned are important and planned.
There’s testing for active infection. It’s main purpose is to mitigate the spread of the virus by identifying people who are carriers. Depending on circumstances, people could certainly be tested repeatedly. Hospital staff springs to mind.
Antibody testing is to see who has had the virus already. That may lead to a “immunity passport” where we can allow those people back to work. More importantly though, it will increase our knowledge of the real spread of this disease and inform future plans.
There are two types of testing. One is looking to see if you’re sick today. We need this so that we can take the asymptomatic carriers of the disease and keep them away from the rest of us. The second is to see if you might be immune from the disease due to already having it. This one will give us idea of where it’s been in our population and get a better handle on where it may be going.
With the first kind of testing you are correct and you may need to be tested multiple times. The idea is we get someone who comes into the hospital who is sick. Then we go back through their history for 2-3 weeks and test every person who they contracted. Then we isolate those people who are sick too and test every person they have had contract with for 2-3 weeks. This way the sick won’t keep infecting new people and the healthy people can go about their lives. Yes if john gets sick and you hung out with him two days ago you’ll get tested and then tomorrow you hang out with Kim who comes down with the disease in a week you’ll get tested again.
In theory the second test to test if you’ve had the disease would only be once if you’re positive but if you come up negative you could need to be tested multiple times. Mostly this one would be a single time since they would want to survey a community and get an idea for the total number of people who might be immune.
Yeah, the paper I read is long on generalities, and short on specifics. Causes me to read less and less.
So, when a governor and/or the fed says add’l testing is needed/planned, any specifics as to who they expect to test how frequently, and how they intend to apply those results?
I guess I should check CDC/WHO - see if they offer any idea as to what would be optimal testing.
It might be useful in understanding rates of transmissibility, too. For example, my stepmother has been on a ventilator for going on a month now. Confirmed positive test. My 79-year-old asthmatic father did not get sick, and did not meet testing criteria because he was asymptomatic. It would be good to know whether he never actually got the virus from my stepmother, or whether he was just extremely lucky to be asymptomatic.
As it was, he had to quarantine for 14 days (which was just fine with him - I think he may never want to leave the house again!). It wasn’t a huge hardship for him to quarantine, but for people in other circumstances, it might be.
There’s also a difference between what we need to do today, and what we need to do when this is a new normal. Like, let’s say a community gets to the point that there are no active infections. Everyone in the community who has any symptoms at all will need to be tested, so that if there is a new flare up, it can be arrested. I mean, it’s honestly not going to be practical to just keep everyone with any sort of cold or allergies home forever: so many people have seasonal allergies. It needs to be to the point that if you are anxious at all that you might have it, you can go get tested easily and inexpensively.
Thanks all, but do you realize that no one has yet really answered my specific question? Not criticizing you - but sorta represents my frustration WRT so many aspects of this thing. And yes, I realize, there is much that is not yet known. (Known unknowns? ;))
What would an expert say is desired in terms of testing? What percentage of the population should be tested, under what circumstances, and how often? I don’t want to say, “Imagine we have unlimited testing”, because I’d like this to reflect what is realistically attainable.
I find it so frustrating and confusing, when persons just say things like, “We need more xyz.” Well, how much more? And for what specific purpose? Put it in terms of dollars, lives, and activity restrictions. Given the amount of coverage my local paper (Chicago Trib) is giving to virus stuff, you’d think they could give more specifics.
So, I read the 2 front page articles in the Trib again.
The article re: Illinois says the goal is to test all nursing home residents and staff, even if the facility has not reported any cases. Doesn’t say whether retests are desired, and doesn’t mention anyone not in or working in nursing homes.
The national article says Kansas want random tests to “sample the population.” It quotes Fauci as saying the US is running 1.5-2 million tests weekly, but we need 2-3x as many. But it doesn’t say who should be tested.
Well, ideally it would be like any survey. You try to test a representative sample of the community, with maybe more emphasis on high density areas because that can blow up faster. If there’s cause for concern, focus on specific neighborhoods as necessary.
Eta: there’s already systems in place to monitor influenza. You could look up what they do for that to get an idea of how future monitoring of this disease might work.
There are multiple tests and multiple goals for testing.
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You want to test folks you suspect of being infected to see if they are actually infected at present. If positive, you’d want to test anyone who the infected person has recently been in contact with. The volume of testing you need to do under this goal is dependent on the current level of active infections.
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You want to test persons who are at high risk of exposure (e.g. health care workers) to determine if any are actually infected at present, so you can isolate/treat them. Ideally, you’d like to test everyone in this grouping weekly to every-two-weeks, but this is the real world and tests cost money. So you do what you can.
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You want to test persons to see if they have previously been infected, on the theory that they may have developed an immunity to the virus. Once per person, assuming accurate tests.
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You want to know how contagious the virus actually is, what the range of symptoms are and what factors cause different populations to present those different symptoms, to what degree prior exposure confers immunity and for how long, i.e. you want to do scientific data gathering. This is the millions per week of testing, and you would try to test randomly to the degree you are able. Again, in an ideal world you’d like to do this so that you can advance understanding and fight the virus more effectively, but tests cost money.