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Rapid COVID saliva test - important for cruising?


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The US FDA approved a rapid 30 min turn around saliva test developed at Yale for COVID.  SalivaDirect. Highly accurate.  Also used by the NBA.

https://abcnews.go.com/Health/fda-authorizes-faster-cheaper-covid-test-push-pioneer/story?id=72396658

 

Others are coming too.  Is this something that will help the cruise and travel industries?  At check in you would do a spit test, wait 30 mins for the results, and the be allowed to board the ship.  I think it could work in the absence (or even the presence) of a vaccine.  Thoughts?

 

 

Edited by TeeRick
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Both the new saliva test, if it proves to be as successful as they predict, and a vaccine would definitely work for us. But I'm not sure we would go if there wasn't an FDA approved vaccine available yet. 

Edited by Ken the cruiser
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Maybe. It’s still rRT-PCR. The EUA notice is on spiked samples, so it works in the lab if the virus is present above the limit of detection. All that is the same as swabs and other rRT-PCR. It’s cheap and essentially non-invasive. 
 

I view it as the same as any other PCR. If the virus is there in sufficient quantity, it should ID it. The challenge of false negatives is the virus isn’t always in the specimen in sufficient quantity, and that’s biology, not laboratory science of engineering. 
 

Unless or until you’re screening with a test that has meaningful false positives, you’re going to miss infected and potentially infectious people. And then you need a test to confirm. 

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To answer the OPs question- Yes, I think it can help the cruise  & travel industries.  
It is unlikely any test will be 100% accurate or that a vaccine will be anywhere near 100% effective so there will always be some degree of risk.  
 

Personally. I would feel more comfortable boarding with this type of test being used vs a test that was done  3+ days previously.

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Thanks TeeRick for the link, it was an interesting read. I think that anything that will make testing faster and more economical is a good thing. There are a couple of draw backs for cruise boarding. What infrastructure will be needed to process say 20,000 samples for 4 ships boarding the same day? I have to assume they will just roll the cost of the test into the price of your fare (with a healthy mark up I'm sure). Then what do you do with all these people while they wait for the test results? Although this is a step in the right direction it's not the solution, just a useful tool in what will be a much bigger tool box. 

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14 minutes ago, Blackduck59 said:

Thanks TeeRick for the link, it was an interesting read. I think that anything that will make testing faster and more economical is a good thing. There are a couple of draw backs for cruise boarding. What infrastructure will be needed to process say 20,000 samples for 4 ships boarding the same day? I have to assume they will just roll the cost of the test into the price of your fare (with a healthy mark up I'm sure). Then what do you do with all these people while they wait for the test results? Although this is a step in the right direction it's not the solution, just a useful tool in what will be a much bigger tool box. 

There have been some hundred different tests.  Most went away quickly as they simply put did not work.

The tests with quick results are being used by many universities in the US to test all students and faculty.  They are being done by the thousands and so far so good.  Estimated cost is under $20 and nothing technical for infrastructure.  30-45 minute wait for test used here.  We wait that long in a lounge to board now.

Interesting comment about a test needing to be sensitive enough to provide false positives lest it would give - heaven forbid - false negatives.  I agree.

The logistics of this are not a big problem and new tests will likely be developed that are faster and more accurate.

The 64K question is does this mean cruising resumes?  Only my opinion with a no. Dear wife has asthma and might be age compromised - has not had a birthday in many many years - so until a good vaccine we will not cruise.

Edited by Arizona Wildcat
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Arizona Wildcat, good to hear that this rapid test doesn't need a big amount of infrastructure. The wait is still an issue, keeping in mind the whole distancing issue waiting for results will require much more space. I think there will be some who really don't care what risk or protocols are in place they will go anyway and either follow the rules or not. There are some (I think the vast majority) who will look at the protocols and decide to cruise or not depending on their personal acceptance of risk. I think my wife and I are in that category, or perhaps the one that will wait a little longer. Then there are those who want a stone clad guarantee of no risk of exposure and a 100% effective and safe vaccine. While they have that right, I wonder how those people ever went travelling in the first place. I do hope that whatever it takes to meet your personal comfort level to travel, it will be reached soon.

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If the accuracy is as good than the existing PCR tests, then the biggest advantage is less discomfort in giving a sample, less need for trained personnel, lower cost per test, so it certainly has some advantages when it comes to testing and getting results back faster.

 

As far as cruising it all comes down to the number of cases in the population the cruisers are coming from.  If you have a relatively low number of cases then it makes a good screening method of the population.  Even with the test false negative rates if you test everyone and get no positive cases and the number of cases in the source population is small, you can be fairly comfortable about the safety of that cruise.  If on the other hand you detect 4 or 5 positives then with test accuracy being what it is, it would suggest that you might have 1 or 2 false negatives making it through.

 

It you look at Europe the issues they have had with COVID during the start up has been more issues with crew being infected then passengers.  What it shows is that even with testing in their home country, quarantine before boarding ship, you still may get positive tests.   That means before the line start up in the US, not only are we going to need much lower case counts in the US, even with testing, but also that the cruise lines are going to have to go to pretty extreme measures as far as testing of crew, quarantine, retesting, etc.  If they try to just bring crew to their ships after one round of testing and then quarantine on board while waiting for passengers I suspect the European experience indicates that they will have problems.

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48 minutes ago, npcl said:

As far as cruising it all comes down to the number of cases in the population the cruisers are coming from.  If you have a relatively low number of cases then it makes a good screening method of the population.  Even with the test false negative rates if you test everyone and get no positive cases and the number of cases in the source population is small, you can be fairly comfortable about the safety of that cruise.  If on the other hand you detect 4 or 5 positives then with test accuracy being what it is, it would suggest that you might have 1 or 2 false negatives making it through.

 

 

I'm going to hit on my pet peeve with reporting how great a diagnostic test is. You've basically hit on predictive value here, which is really important. But sensitivity, specificity, and limits of detection are almost always reported by lab types based on the device. I've got great confidence the device here will identify the virus if:

 

1) The specimen is obtained at a time during the infection when the virus is present in the specimen sampled (nasal swab, saliva, etc.).

 

2) It's present above the limits of detection of the device.

 

3) The device performs correctly (positive and negative controls are appropriate, at a minimum).

 

#1 is where I have serious questions, and that's not a device problem, or something that can be engineered. The EUA is based on spiking saliva samples; I don't see any data on how often you actually find the virus in the saliva in asymptomatic/presymptomatic individuals. Or for that matter, symptomatic individuals. I assume some of that's out there and I simply haven't looked for it. The EUA basically is based on chemically removing saliva inhibitors to run the PCR. When in the process of infection and disease is the virus in saliva? That's key to believing a negative test result, especially if I'm using it as a screening tool to exclude the infected/infectious. If the device did not find viral RNA; should it have been there at that point in time anyway? Would it be positive an hour later? Twelve hours later?

 

I'll stick with the notion that this test appears to be inexpensive and pretty much non-invasive, but it hinges on data that shows when the virus should be in saliva relative to exposure, the ability to transmit, and symptoms.

 

 

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12 minutes ago, markeb said:

 

I'm going to hit on my pet peeve with reporting how great a diagnostic test is. You've basically hit on predictive value here, which is really important. But sensitivity, specificity, and limits of detection are almost always reported by lab types based on the device. I've got great confidence the device here will identify the virus if:

 

1) The specimen is obtained at a time during the infection when the virus is present in the specimen sampled (nasal swab, saliva, etc.).

 

2) It's present above the limits of detection of the device.

 

3) The device performs correctly (positive and negative controls are appropriate, at a minimum).

 

#1 is where I have serious questions, and that's not a device problem, or something that can be engineered. The EUA is based on spiking saliva samples; I don't see any data on how often you actually find the virus in the saliva in asymptomatic/presymptomatic individuals. Or for that matter, symptomatic individuals. I assume some of that's out there and I simply haven't looked for it. The EUA basically is based on chemically removing saliva inhibitors to run the PCR. When in the process of infection and disease is the virus in saliva? That's key to believing a negative test result, especially if I'm using it as a screening tool to exclude the infected/infectious. If the device did not find viral RNA; should it have been there at that point in time anyway? Would it be positive an hour later? Twelve hours later?

 

I'll stick with the notion that this test appears to be inexpensive and pretty much non-invasive, but it hinges on data that shows when the virus should be in saliva relative to exposure, the ability to transmit, and symptoms.

 

 

I recall reading one study that compared different sample spots (throat, nose, saliva) to compare methodology for detection.

 

From what I recall saliva was not much different than the deep nose tests.  I will see if I can find that study.

 

I do not recall the study looking at how infectious the patients were, only a comparison between patients where all three samples were taken at the same time to compare the sample methodology, 

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I could not locate the original study but here are a couple of others that I ran across on the topic.

 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7270800/

Comparison of SARS-CoV-2 detection in nasopharyngeal swab and saliva

 

https://www.ecdc.europa.eu/en/covid-19/latest-evidence/diagnostic-testing

Diagnostic testing and screening for SARS-CoV-2

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10 minutes ago, jelayne said:

OMG!  This thread went way over my non-scientific head.  
I appreciate all your scientific knowledge but just want to know ( in layman’s terms) is this a viable option?


I’d tend to say yes. It appears to be similar to the swabs, but it’s primary use had been for near continuous monitoring in the NBA bubble. It should ID a similar population as the swabs, but it will likely miss a similar population. I think the NBA was sampling every day or every other day, which theoretically could offset the infectious but not symptomatic population, and they’re isolating positives and quarantining contacts. 
 

Sorry about that. The point is the method is only as good as the specimen, and most of the false negatives today are probably from sampling at the wrong time. A better device really doesn’t help that; it’s just easier to use. 

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6 hours ago, jelayne said:

OMG!  This thread went way over my non-scientific head.  
I appreciate all your scientific knowledge but just want to know ( in layman’s terms) is this a viable option?


Is this test likely to be used when cruising restarts if it’s pre vaccine? Yes. Would it be helpful? Yes. Is it a magic bullet that will return cruising to ‘normal’? No. A negative result is not proof that you are Covid free, especially if you only picked it up recently (like traveling to the port). Over enough sailings they will still end up boarding someone(s) with Covid. It’s simply 1 tool that will need to be used in conjunction with other tools (temp checks, social distancing, etc).

 

but the thing to think about before jumping to book a cruise like this is what happens if you end up testing positive? Probably can’t board a plane to fly home. Def can’t board the ship. Could get stuck with your family paying for a hotel room for two weeks where you can’t leave your room.

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I agree that without getting into all of the caveats, a rapid and accurate 30 min turn around test is a big help to get cruising going again and adds to the safety overall.  No test will be perfect.  There will still be breakthrough cases.  Unavoidable.  But if there are enough analyzers and reagents for all passengers and crew at preboarding, I think this will be a valuable addition.  A good tool.  And if testing could be done rapidly on board during the cruise as necessary, even better.  Right now where I live, It is 3-4 days to get just an appointment for the nasal swab PCR test.  And then 6-10 days for a result.  What is the point if you have to self-quarantine for this same period anyway? 

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3 hours ago, sanger727 said:


Is this test likely to be used when cruising restarts if it’s pre vaccine? Yes. Would it be helpful? Yes. Is it a magic bullet that will return cruising to ‘normal’? No. A negative result is not proof that you are Covid free, especially if you only picked it up recently (like traveling to the port). Over enough sailings they will still end up boarding someone(s) with Covid. It’s simply 1 tool that will need to be used in conjunction with other tools (temp checks, social distancing, etc).

 

but the thing to think about before jumping to book a cruise like this is what happens if you end up testing positive? Probably can’t board a plane to fly home. Def can’t board the ship. Could get stuck with your family paying for a hotel room for two weeks where you can’t leave your room.

OK definitely agree that this is one big issue.  Hopefully this would be procedurally worked out by the cruise line  and port as this will happen every cruise.  But is your alternative not to take the test and not know if you are positive and infectious? and perhaps sick too?

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2 hours ago, TeeRick said:

OK definitely agree that this is one big issue.  Hopefully this would be procedurally worked out by the cruise line  and port as this will happen every cruise.  But is your alternative not to take the test and not know if you are positive and infectious? and perhaps sick too?

 

My alternative is not to take a vacation that requires a covid test during the trip. I would be willing to take a covid test before the trip. Difference is if I take the covid test at home and it's positive, trip is cancelled, no extra time wasted, and can quarantine at home. If I fly to another city for a trip and take a covid test there, now I"m stuck spending more time on the trip than I intended, wasted time traveling, and stuck in a hotel to quarantine rather than at home. 

 

As far as your last bit about being unknowingly positive and infectious. Isn't that your every day life now? I certainly don't get covid tests daily, I could be infected and asymptomatic/presymptomatic at any point. That's why I wear a mask and socially distance; but no not going to get hung up every day on not getting a new covid test.

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I have the same thought about testing at the port  and during a cruise.

If  a pre cruise test at embarkation  is positive, you  then could be standing there with luggage, no transportation or place to stay during quarantine..

The cruise line will claim it is not  obligated, the Port Authority  and hotels/ hospitals won't want you and airlines will ban you.

 

At least at home you  have options..

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11 minutes ago, hcat said:

I have the same thought about testing at the port  and during a cruise.

If  a pre cruise test at embarkation  is positive, you  then could be standing there with luggage, no transportation or place to stay during quarantine..

The cruise line will claim it is not  obligated, the Port Authority  and hotels/ hospitals won't want you and airlines will ban you.

 

At least at home you  have options..

Maybe the solution is for cruises only from people's home ports or where they can drive to? At least until a vacine is developed and most people have some level of immunity 

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On 8/16/2020 at 5:52 AM, TeeRick said:

The US FDA approved a rapid 30 min turn around saliva test developed at Yale for COVID.  SalivaDirect. Highly accurate.  Also used by the NBA.

https://abcnews.go.com/Health/fda-authorizes-faster-cheaper-covid-test-push-pioneer/story?id=72396658

 

Others are coming too.  Is this something that will help the cruise and travel industries?  At check in you would do a spit test, wait 30 mins for the results, and the be allowed to board the ship.  I think it could work in the absence (or even the presence) of a vaccine.  Thoughts?

 

No, it will allow for reopening of much of the economy but not cruising.  The issue is its poor sensitivity.

 

The epidemiological idea behind it is that lets say base R0 ~ 3.  The goal is to get R0 < 1, so that you have decreasing number of cases.  All the different policies that the governments are trying to do will decrease this base R0.  Right now the only thing that really gets R0 < 1 seems to be a massive shutdown.  But with widespread mask usage, and widespread saliva testing, even if the testing isn't perfect, it may decrease the R0 by a large amount, and let you "spend" that decrease somewhere else.  Like say school reopening.  Or more in person businesses. 

 

The problem with cruises is that once you let someone slip through, it becomes a HUGE problem.  One case on a week long cruise = 300 infected.  So if the test is only like 70% sensitive, then how low does the population incidence have to be before it's safe to cruise with 5000+ pax ships so not one person will have the virus?  I don't think it's happening without a vaccine.

 

I can see it used in conjunction with a vaccine in the early days to start up a little quicker while not everyone is vaccinated. Or if there are issues with vaccine efficacy there may be a role. 

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https://sports.yahoo.com/the-nba-and-yale-just-landed-the-covid-testing-breakthrough-the-nfl-and-everyone-else-in-the-us-has-been-hoping-for-183335566.html?guce_referrer=aHR0cHM6Ly93d3cueWFob28uY29tLw&guce_referrer_sig=AQAAABIh6_mgLPQY3ql7xtrQI8Yo3f3x3onLSNhMECpydWEmTq3b19AQndsgjMlmrKGGrw1LrdM7es0pF4i8rz1x9yyh1-8u6w1oalDwI0t8apQHQn1sTiFaSMLEIxOrqTMH0-3TMb_JcxCRPcyuLiDrypvveeRP1neXX59LCca1TcXh

 

 

They are using this test to bring kids back on campus--Penn State sent a test to every student. I hope it is accurate!

 

I also love this: "Developed by Yale University and jointly funded by the NBA and NBA Players Association" 

 

Great work putting up the money NBA & NBA players association! 

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