[0] https://www.fda.gov/medical-devices/coronavirus-disease-2019...

[1] (pdf) https://www.fda.gov/media/141570/download

[2] (pdf) https://www.fda.gov/media/142193/download

[3] (pdf) https://www.fda.gov/media/152698/download

[4] (pdf) https://www.fda.gov/media/147494/download

Ripped straight from https://www.bio-rad.com/en-us/life-science-research/overlay/...

Swab throat too during rapid COVID test, Israel's Health Ministry says

https://www.reuters.com/business/healthcare-pharmaceuticals/...

So what's better, getting your throat spit up your nose, or getting your nose mucus in your throat?

Every time you sniff, you get nose mucous in your throat (what with them being connected and all), and when you sneeze quite a bit of throat mucous will is drawn up along with air. And now remember that your intestines are physically connected to your mouth by only a foot or two of squishy pipe and you'll be wishing for a nice clean robot body.

U.S. diplomats in China were subjected to anal swab tests for Covid-19, a Department of State spokesperson confirmed Thursday, adding that a protest had been lodged with the Chinese Ministry of Foreign Affairs.

https://www.nbcnews.com/news/world/u-s-diplomats-china-subje...

Anecdotal: I was in my 3rd of 4th day of symptoms before I finally came up positive on antigen (at home and at testing sites; the test appeared to be the exact same). PCR showed it from day 0 but the results lag quite a bit especially right now in the US (it took 7-10 days for me to get the PCR back in early Jan).

LFDs are decent for telling you if you're infectious _right now_ - they're much worse than PCRs for telling you if you have covid at all.

Disclaimer: I'm a software engineer, do not take medical advice from me. My partner is a biochemist and I regularly chat with a couple of council covid-response officers, and the above is the explanation I've had from them when I've asked.

If only we had some guidance and solid communication from public health experts that you could conceivably trust..

Like the grandparent, I know several people that have all of the covid symptoms, but tested negative early on. These people just go about their day because they think they have some other cold, then stop testing until their symptoms go away. I would probably do the same.

You drive into a parking lot, they hand you a test, you self-swab and give it back to them.

There is other testing available - this is just the county-provided testing. It’s well run.

The place I use in Austin is $85 for a same day PCR test.

Ever since the vaccines came out and were implemented in full force, I am wondering what the purpose of testing even is. At least in the US, even the most restrictive locales have no intention of shutting down commerce to limit transmission. I do not know anyone who is not treating this coronavirus like any other, or the flu, or a rhino, or whatever other sicknesses normally go around.

My kids' daycare (or local government, not sure which is responsible) has a crazy policy of shutting down a class for 2 weeks if a covid case is detected. But not if any of the kids are sick with RSV/flu/rhino/noro/rota, etc. The daycare has not had any reports of covid for months. I am pretty sure all the parents are simply choosing to not get their kids tested because who can afford to drop their obligations for 2 weeks and also force all the other parents in class to do the same. Every single kid walking through those doors has a snotty nose, and surely at least 1 has had covid 19 over the past few months.

It all seems similar to security theater after 9/11. A lot of effort and expense for little gain so somebody can say they did something.

If I isolated every time I got the sniffles or was more tired than usual I'd be home a lot..

https://pubmed.ncbi.nlm.nih.gov/33015684/

Society's risk tolerances are being very inconsistent right now, and the only reason I can see is for political purposes (i.e. cover your ass).

By the way, I'm not claiming we should be more strict about any of this, but on a personal level I'd rather do my best to not infect others.

I guess what I am getting at is the dichotomy of leaders officially acting if people should test and quarantine and all that jazz, while obviously knowing that those who need to go out and work to put food on the table and funds in the retirement account will continue to do so.

Based on the stats, I would bet all I have on one of those snot nosed kids at my kids' daycare having covid right now. But I am sure many or most of the parents need to work for the cash to meet the mortgage payments or whatever their expected quality of life is.

I do agree there's a lot of hypocrisy and ass-covering going on. Even earlier in the pandemic healthcare workers were discouraged from getting tested so they wouldn't need to stay home from work. I think making tests available prevents at least some unnecessary transmission which is good enough for me.

https://ourworldindata.org/covid-deaths-by-vaccination

Which, if daycares were run by the toddlers independently of adult supervision, would be a great point.

I get the initial lockdowns and period of time to figure out this new thing, but at this point in time, I do not see how people's risk profile is any different than what it was before Dec 2019.

There are virtually zero deaths attributable directly to flu by hospitals. The vast majority are imputed by estimated excess deaths.

So even by completely different and unfair metrics, covid is vastly more dangerous. If you went by that standard covid likely has claimed over a million US deaths already, compared to a few tens of thousand for flu.

https://www.cdc.gov/nchs/nvss/vsrr/covid19/excess_deaths.htm

On top of that, covid has a significantly higher R0 value, which means you’re much, much more likely to come into contact with it.

That’s how you change your risk calculation: it’s the cost of getting it (probability of death or maiming) times the probability of getting it (community spread level and nasal viral shedding rate). There is no mitigating factor here wrt covid vs flu risk.

You can’t isolate if you don’t know you’re sick.

  1. Things such as influenza mostly spread when the person is symptomatic.
  2. Something along the lines of 50% of covid infections are from pre-symptomatic and asymptomatic people. Self isolating when you have symptoms is certainly good, but it is by no means the entire picture.

If you test positive, you're supposed to stay home and isolate so you don't spread COVID.

Tests aren't perfect, since as you said, there seems to be a significant false-negative rate with Omicron, and you can be contagious before you show symptoms, but the tests help prevent people from spreading confirmed cases, and can be helpful to pre-test before you spend time with someone who is at high risk for COVID.

Its not even Omicron. Rapid tests always had something like a 40% false-negative rate or something stupidly high.

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That's why you're supposed to take two tests if you're asymptomatic, to reduce the chances of a false-negative.

Fortunately, the false-positive rate is less than 5% IIRC, and fairly reliable.

EDIT: Sensitivity and Selectivity isn't really false-negatives or false-positives. But for the purposes of this discussion, its probably good enough. Besides, I'm just an ignorant programmer who doesn't know the difference between them.

https://www.bizpacreview.com/2021/12/29/fda-says-rapid-at-ho...

“RADx recently performed preliminary studies evaluating the performance of some antigen tests using patient samples containing live virus, which represents the best way to evaluate true test performance in the short-term. Early data suggests that antigen tests do detect the omicron variant but may have reduced sensitivity,” according to the FDA.

Frankly, going from 60% to 40% doesn't change my viewpoint on rapid tests. Its all "unreliable false negative" to me (I don't know what it is for Omicron, I'm just pulling 40% out of nowhere). But whatever it was, the sensitivty was always so low that you never could rely upon a negative-reading, due to the high chance of false-negatives.

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Rapid tests remain useful, but you _MUST_ always be mindful of their high false negative rate. The fact that their "unreliable stat got even more unreliable" isn't really news, because you shouldn't have been relying upon it anyway.

Rapid tests give you a result within 15 minutes. PCR tests you gotta ship to a lab, and wait maybe 2 or 3 days before they report back to you.

I think PCR tests (which nominally take 15 minutes) are the best. But we clearly don't have the infrastructure to support it. Every lab doing PCR tests is going at full throttle and yet we still have this 2 or 3 day delay everywhere.

Meanwhile, at-home rapid tests work immediately. They're way less accurate, but its better to have some degree of testing rather than nothing at all.

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Lets say you have a workforce consisting of 10 people who are sick with COVID19 right now. PCR tests might catch 9/10 of those people. Rapid tests might only catch 6/10.

But removing those 6-people with Rapid tests in your workforce will slow down the spread. 4-people spreading COVID19 in your workplace is better than 10-people spreading COVID19.

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EDIT: More importantly, Rapid tests will catch those 6 people _TODAY_. PCR tests will take ~3 days before they report back, meaning if you're on PCR-tests only, your COVID19 positive people will be around the workforce for 3 days.

If you use both Rapid Tests + PCR tests, you remove those 6 people _TODAY_ from the workforce (meaning 4 people will be spreading COVID19 in your workforce). 3 days later, those 3 other people are removed which is "too late". The Rapid test was in fact more useful.

PCR tests are better for contact tracing, due to their higher reliability. If someone tests positive with PCR tests, you trace their contacts and tell _THOSE_ people to get PCR tests and/or rapid tests, in an attempt to "get ahead" of the disease. (IE: those 3 people who weren't caught by rapid tests were in contact with 15 people total. You now tell those 15 people to rapid test + PCR test).

Rapid tests _always_ had bad sensitivity. Its gotten worse for Omicron, but going from "bad" to "worse" isn't really a big deal, because you never should have been relying upon negative test results anyway.

That's my point. The "use" of rapid tests was their "rapid" nature, coming back with a result in 15 minutes is way better than waiting for 3 days. The PCR is needed if you want to truly rely upon the result (well, kinda sorta. PCR got better sensitivity / specificity but its still not perfect).

The rapid tests are still quite useful because a positive test is very reliable and saves you several days of waiting for PCR results.

Perhaps the test results should be labeled "Yes, you have covid", and "meh, not sure".

When my son tested positive, they refused to let us re-test to see if it may have been a false positive. He's 2 and was completely asymptomatic.

She also thought it would be helpful to know if exposure = any additional immunity down the road, since all of the facts constantly change

There are other possibilities like that she had a cold and the 5th test was a false positive or she had a cold and got covid several days later.

PCR tests will report COVID infections that are way below the threshold of transmissibility, and they'll keep reporting positive results long after the infected person is no longer contagious.

"Am I contagious?" is arguably a more useful question to answer than, "Do I have any detectable amount of COVID in my body, at all, using the best laboratory testing processes available?"

[1] https://yourlocalepidemiologist.substack.com/p/antigen-tests...

[1] https://www-umcutrecht-nl.translate.goog/nieuws/corona-zelft...

Covid is much more dangerous for the elderly than the young, even vaccinated. The young are so safe that there have been ~250 total covid deaths in the US age 0-4.

Also, there is growing evidence that the lateral flow tests correlate well with being infectious.

Testing reasons:

For lots of staff (medical, school, factories), to avoid unnecessary prophylactic isolations, particularly for people whose work cannot be done remotely. And for the same group of people, testing daily (were we in a competent country with the test manufacturing to support) could significantly reduce community spread. Daily tests are infeasible to do with pcr if for no other reason than the reporting lag.

For visiting high risk people: reasonably reliable, fast indicator of whether you have covid in order to make near realtime decisions about activities to engage in. Like masks, this will reduce community spread.

My understanding is:

1) Existing rapid tests are not as sensitive to Omicron as previous variants.

2) Negative results on rapid tests are unreliable, especially single negatives. They're more reliable when taken in series, and the instructions for the ones tell you to take two tests, 3 days apart. However, their positive results are very reliable, so if only 75% of the positive people who take one actually test positive, you've still successfully detected 75% of those infections.

PCR tests are far better at detecting infections early.

If you are in the US, flu is a possibility. Unlike 2020-21, the 2021-22 flu season is coming on strong: https://www.cdc.gov/flu/weekly/usmap.htm

This won't help us get a handle on asymptomatic cases - to do that, we'd have to be able to test everyone on a frequent and consistent basis.

This program doesn't even cover one test for everyone in my house, let alone weekly or more frequent testing. And aside from this, I have to spend hours looking for any available rapid tests to buy around here, and if/when I have some, I can't afford to use them on randomized or even weekly testing.

> QuickVue At-Home OTC COVID-19 Test correctly identified 83.5% of positive specimens and 99.2% of negative specimens.