7 ms·

I have an interesting anecdote related to this. As it happens, I currently have COVID. When I first noticed I was getting sick, I was scheduled to fly in the n

by nilkn 6y ago

I have an interesting anecdote related to this. As it happens, I currently have COVID. When I first noticed I was getting sick, I was scheduled to fly in the near future, so I got a rapid COVID test that delivers results in 15 minutes. It was negative. I got another one, and it was negative too. I had thus intended to go ahead with the trip under the assumption I had a minor cold. Later, a few days before I was to fly, I lost all smell and taste. Now I didn’t know what to think. I wasn’t particularly congested, and the loss of smell was total. I’d never experienced this before. Could both tests have been false negatives? I delayed the flight (free of charge luckily, so no big deal) and got a test that had to be sent to a lab for analysis. A week later, the positive test result came back. Take from this what you will. I'm not a scientist or a doctor and frankly there's nothing remotely intelligent I can say about the various tests out there for COVID. But if the rapid tests are as unreliable in general as they were for me, it’s sort of no wonder COVID is spreading like wildfire. I was very, very close to boarding a plane with an active case of COVID, and I would have if I hadn’t acted out of an abundance of caution.

dragonwriter 6y ago
Rapid tests are known to be unreliable and particularly have a high false negative rate. That's why all the guidance has been that rapid tests can be used to indicate infection but not rule one out, and none of the screening processes based on exposure and symptoms accept “but I also had a negative rapid test” as neutralizing a flag on any screening factor. > I would have if I hadn’t acted out of an abundance of caution. The bare minimum of caution with a rapid test is treating a positive as a true positive and a negative as an indicator that you need a regular test. That you understood your actions to be an abundance of caution demonstrates a failure to effectively communicate on some level (I'm not saying that you are culpable; the information is out there's but delivery is...mixed, even before considering how it is muddled by misinformation from various sources.)
- nilkn 6y ago
  I definitely think there's a communication deficiency or breakdown happening, because none of the medical professionals indicated to me that the rapid tests were that unreliable when it comes to producing false negatives. I also feel personally guilty for not having been as well-informed as I should have been. I'm just glad I experienced a tell-tale symptom (loss of smell/taste) and was able to act on it before boarding a plane. Another interesting aspect of this is that prior to experiencing loss of smell/taste, I was more or less told by urgent care staff that I didn't have COVID, and they were pretty resistant to testing me -- hence I only got rapid tests. Yet I actually was right in the midst of an active case.
  - cbo100 6y ago
    You mentioned it was a few days between the initial negative rapid tests and the positive lab test. Would be interesting to know the result of another rapid test at the same time as the lab one. Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive?
    - weaksauce 6y ago
      > Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive? they do require a higher viral load than the pcr test to accurately show infection. the pcr test studies have shown to be 0-30% false negative later in the illness after symptoms have shown (when there are fewer antigens in the body). both the pcr and the rapid tests are expected to have a near 0% false positive rate though with most false positives being lab contamination or mishandling. even if the test is 50% false negative(not the actual number) it would still drastically slow the spread of the virus coupled with other measures. This is more of a defense in depth instead of a firewall; the swiss cheese layers of threat reduction.
  - whimsicalism 6y ago
    Rapid tests are just a gamble if you want to save time/money/exposing others if you end up being positive. If you're negative, you then have to get the actual test, but if you're positive you can probably start isolating now.
    - nip180 6y ago
      > if you’re positive you can probably start isolating now. If you experience symptoms you should start isolating, regardless of the results of a rapid test.
      - midasuni 6y ago
        It’s the people without symptoms. Doing a regular test every few days will prevent at least some spreading if you are a symptomless carrier
pvarangot 6y ago
Thanks for your anecdote. When SF was doing better and the possibility of big outdoor events with testing on the door were something that was being discussed, I looked at rapid tests together with some friends and the accuracy is really appalling. People relying on this to "safety socialize" may be one of the issues making cases rise in California, the math adds up. Many people reached to the government saying they should stop sponsoring and advertising rapid test sites because the false sense of security may be really doing more harm than good. One of the rapid tests that we considered has, as advertised by its own manufacturer, a 10% false positive rate on basically all the population, and a 50% false negative rate even on symptomatic individuals with high viral load. Do the math, but using that type of test in something like for example a 100 person event or a restaurant will result in people being turned out of the door daily even if they were not symptomatic, and at least one or two people with high viral load being admitted into your place. I can't find the link of the test now, but there's better data about how harmful rapid tests are when not used together with PCR testing, for example here: https://www.bmj.com/content/371/bmj.m4941 https://www.bmj.com/content/371/bmj.m4941 and here: https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Se... That's why most countries that really thought this through require a recent PCR test result for admittance. It's really not clear what benefits rapid tests have if you don't have a model for population behavior. I think at lest the SF government is only doing them to save face now that the cat is out of the bag.
jonny_eh 6y ago
I hope you get well soon!
DeRock 6y ago
Whether a test is positive or not depends highly on what type of test it is, and when you are tested relative to symptom onset. You can absolutely be carrying the COVID virus but still test negative. Heres a paper with a handy chart: https://jamanetwork.com/journals/jama/fullarticle/2765837 https://jamanetwork.com/journals/jama/fullarticle/2765837 I think you testing negative was a combination of the rapid test being unreliable, as well as getting tested early with respect to symptoms.
jedberg 6y ago
This rapid tests have a very high false negative rate. The result you get back should really be "You have COVID" or "You may have COVID, get a PCR test".
graeme 6y ago
Rapid tests are at their most accurate when someone is at their peak infectiousness. Accuracy declines swiftly before or after that. So the use you made of them didn’t fit their ideal use case, as you used them several days before travel. Even then, with symptoms, I am not sure they would be enough to rule out a positive. The biggest use of rapid tests is finding additional positives that would not otherwise have been found.
situationista 6y ago
Most countries which require a test for entry stipulate it must be a PCR test rather than a rapid (antigen) test. I’m currently in Lisbon waiting for the results of a 24h PCR test in order to board a flight to Azores, for example.
option 6y ago
note that rapid test is still useful to confirm infection. But, yes, much more unstable for ruling out one
Osmium 6y ago
I'm glad the OP made the correct decision in this case and hope they get well soon. > the assumption I had a minor cold > the loss of smell was total Since there does seem to be a messaging problem about the reliability of testing, I think it's worth emphasizing: if someone has symptoms of COVID, they should proceed as-if they have COVID. CDC guidance[1] is to isolate if you have a positive test OR if you have symptoms. To do otherwise is to gamble with the health and lives of the people they meet, and the people those people meet, and so on. It may prove almost impossible to show who caught COVID from whom, but that doesn't mean that ignoring guidance won't lead to deaths. A statistical death is still the death of a real person, even if we can't put a name to them. [1] https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/isolation.html https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/is...
- nilkn 6y ago
  To be clear, the order of events was such that I did not have loss of smell/taste at the time of the rapid tests. There was no indication at that time of anything that wasn't completely consistent with and expected from a cold, and I even encountered resistance when I tried to get tested prior to the tell-tale loss-of-smell symptom appearing (hence the rapid tests only at that point). I had a mildly uncomfortable phone call with an urgent care center where they discouraged me from pursuing testing because they didn't think I had enough symptoms. I knew exactly from whom I had contracted whatever illness I had, and that person had also tested negative for COVID (upon further questioning, their test had also been a rapid one, and they too had not been informed of its unreliability for any negative determination).
  - bigiain 6y ago
    > There was no indication at that time of anything that wasn't completely consistent with and expected from a cold Unfortunately, I think these days symptoms of "just a cold" are enough reason to self isolate for long enough to reliably get through the Covid incubation period - which locally (Sydney .au) has been reported to occasionally be as long as 10 days or more.
    - 6y ago
koyote 6y ago
> A week later, the positive test result came back Which country do you live in that it takes a week for the PCR test to come back? It's around 24 hours here and I thought that was the case in all developed countries. I hope you recover quickly!
- nilkn 6y ago
  I'm in the US. The test was taken on a Sunday evening at about 7:30PM, and the results were delivered via text message the morning of the following Friday. My guess is there's a lot of variability in how long it takes to get results. I know folks who've taken the same test and they got results back within 48 hours.
  - zo1 6y ago
    South Africa here. I've known people that got their test back in less than 24 hours
    - markus92 6y ago
      Netherlands here, I routinely get them back within 8 hours after taking the swab. At work (hospital), we can get them within an hour if it's urgent.
  - kelnos 6y ago
    There's a lot of variability, and it depends on how far you are from the lab the particular test center uses, how quickly the test center sends your sample to the lab, and how busy the lab is. I've had two tests that came back in around 48 hours and one that only took 8 hours (US, SF bay area). 4.5 days seems pretty excessive (and frankly pretty useless) though!
- bigiain 6y ago
  > Which country do you live in that it takes a week for the PCR test to come back? I'd guess a country with a totally dysfunctional, practically 3rd world medical system, with deeply entrenched profiteering and usury. So most likely the USA?
glandium 6y ago
Note that even PCR tests have a relatively high rate of false negatives.
arcticbull 6y ago
If you still have yet to test positive for COVID you may not have COVID. A loss of sense of smell and taste is a common symptom of a viral infection.˜ [1] [1] https://www.healthline.com/health/coronavirus-loss-of-taste-loss-of-smell#an-early-symptom https://www.healthline.com/health/coronavirus-loss-of-taste-...
- bigiain 6y ago
  Yeah - so you should probably go to a political rally or concert or a nightclub or something!!! :sigh: This is awful advice for 2021. (Even though _technically_ it's correct.) If you have a loss of smell/taste you should 100% assume you have Covid and act accordingly, get tested immediately, self quarantine for probably 14 whole days, and get retested at around 10 days. If you have "mild cold/flu symptoms" you should assume you like;y have covid, and should get tested (not with a "rapid test") and self isolate until you get a negative result. Truth is, even with no symptoms, you could have Covid. If you've been in contact with anyone who has cold/flu symptoms, or been to a place where someone with a positive covid test has been - you should get tested (and probably self isolate until you get a negative result). From: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774707 https://jamanetwork.com/journals/jamanetworkopen/fullarticle... Results: The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms. Conclusions and Relevance: In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.
devy 6y ago
> But if the rapid tests are as unreliable in general as they were for me, it’s sort of no wonder COVID is spreading like wildfire. Many rapid tests are indeed not accurate[1] but they still serve a purpose, depending on the sensitivity and specificity of the tests[2]. For the rapid tests with high sensitivity and you get a positive result, it's highly likely you have COVID. For the rapid tests with high specificity and you get a negative result, it's highly likely that you don't have COVID. And the public health measures of testing / contact tracing ONLY works if testing results come back quick. PCR tests are neither fast nor cheap, so those are not as effective in prevention of spreading because you don't do those all the time (slow + expensive). Medcram has a good video talking about this. [3] [1]: https://www.wsls.com/news/local/2021/01/08/cdc-study-shows-covid-19-rapid-tests-not-as-accurate/ https://www.wsls.com/news/local/2021/01/08/cdc-study-shows-c... [2]: https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity [3]: https://www.youtube.com/watch?v=h7Sv_pS8MgQ https://www.youtube.com/watch?v=h7Sv_pS8MgQ
- kelnos 6y ago
  I only have data points for two different testing orgs, but in my area, GoHealth charges $250 for a rapid test, and Color charges $110 for a PCR test[0]. So it seems like that's flipped from what you're suggesting? The Color tests can even come back in 8 hours or so, if you're not too far from a lab and the lab isn't overloaded. Not as fast as 15 minutes, and certainly higher variance, but much more useful than 72 hours people normally assume. Regarding false negative rate, Hawaii is accepting some of the rapid tests (like the aforementioned GoHealth test) for pre-travel screening, which is concerning. [0] These are both without involving insurance at all. It's possible, though, that the Color tests are partially subsidised by Google?
  - calvano915 6y ago
    Simply, $250 is a scam given the limitations of that type of test. Its simply a money grab from those unaware. Its been known for months that PCR is the gold standard, and rapid tests are not. Rapid tests are good for surveillance but not diagnosis.
Reason077 6y ago
Rapid tests (aka: Antigen tests, or lateral flow tests) are high specificity, low sensitivity tests. That means they’re biased towards the negative side: they’re unlikely to return false positives, but quite likely to give false negatives. Such tests are useful for epidemiological studies, or for answering the “do I have Covid antibodies?” question. But they’re not a reliable way to actually test for Covid. You need a PCR test for that!
anonytrary 6y ago
If you don't mind, can you please share your age or a ballpark estimate? It seems like you are doing well and just had the minor symptoms.
- nilkn 6y ago
  Sure, I'm in my early 30s. I do believe I had a pretty mild case all things considered, and I'm pretty much fully recovered at this point but still plan to quarantine for another week. What I experienced was basically indistinguishable from a mild cold except for the loss of smell and taste, which took over a week to show up after the onset of the initial symptom (a fever). While I know loss of smell can happen from non-COVID infections, I can say this is the only time in my life I've had a total loss of all smell and taste. I'm very fortunate that this total loss only persisted for a few days, and at this point based on my subjective experience my smell and taste senses appear to be normal again.
lol768 6y ago
They've been using these lateral flow tests in the UK quite a bit - particularly for university students returning home/to campus (or at least, that was the plan!). But I'm not convinced the data on their effectiveness really supported using the tests in this way: https://twitter.com/deeksj/status/1340975400726478849 https://twitter.com/deeksj/status/1340975400726478849 But it was a political "win".
maxerickson 6y ago
What entity approved the test for distribution?
argonaut 6y ago
There are many different rapid tests. Some are reliable and some are unreliable. For the ones that are reliable (like Abbott's test), they are highly accurate at determining whether someone is currently infectious. So you could have been infected but not capable of transmitting to others yet. These tests would be highly useful for onsite testing, such as if airlines required a rapid test right at the airport.
Tainnor 6y ago
> I have an interesting anecdote related to this. Please don't do that. There is enough knowledge out there about the various kinds of tests (PCR, antibody, antigene) and what they're good for and what they're not. It's perfectly understood that while rapid tests are, well, rapid, they're much less precise than PCR testing. However, they are often better than nothing (you can't give a PCR test to everyone who wants to visit relatives in a nursing home), so they serve to minimise risk, not to remove it. (They also have a tendency to be more likely to be positive while you're actually infectious, which is not the same thing as having symptoms.) I really don't think we should be discussing personal anecdotes during a health crisis, when there's enough data around that we can actually look at.
- deleted 6y ago
  [deleted]
raxxorrax 6y ago
The most common error with these tests is false application. Did you have someone else doing the swab? It has to feel like someone is poking at your brain.
Technically 6y ago
How is this related to the story? Why waste my time like this? Provide or shut the fuck up—that's how hacker news works for successful assholes.
luisvel88 6y ago
You were probably not contagious during those first days (at least for everyone except your partner).The threshold for the rapid test is higher than what the PCR detects. The antigen test is highly reliable for catching contagiousness, not just any viral load. Michael Mina (Harvard Biologist) presents the data in a great way if you want to check.

by nilkn 6y ago

dragonwriter 6y ago

Rapid tests are known to be unreliable and particularly have a high false negative rate. That's why all the guidance has been that rapid tests can be used to indicate infection but not rule one out, and none of the screening processes based on exposure and symptoms accept “but I also had a negative rapid test” as neutralizing a flag on any screening factor. > I would have if I hadn’t acted out of an abundance of caution. The bare minimum of caution with a rapid test is treating a positive as a true positive and a negative as an indicator that you need a regular test. That you understood your actions to be an abundance of caution demonstrates a failure to effectively communicate on some level (I'm not saying that you are culpable; the information is out there's but delivery is...mixed, even before considering how it is muddled by misinformation from various sources.)

nilkn 6y ago
I definitely think there's a communication deficiency or breakdown happening, because none of the medical professionals indicated to me that the rapid tests were that unreliable when it comes to producing false negatives. I also feel personally guilty for not having been as well-informed as I should have been. I'm just glad I experienced a tell-tale symptom (loss of smell/taste) and was able to act on it before boarding a plane. Another interesting aspect of this is that prior to experiencing loss of smell/taste, I was more or less told by urgent care staff that I didn't have COVID, and they were pretty resistant to testing me -- hence I only got rapid tests. Yet I actually was right in the midst of an active case.
- cbo100 6y ago
  You mentioned it was a few days between the initial negative rapid tests and the positive lab test. Would be interesting to know the result of another rapid test at the same time as the lab one. Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive?
  - weaksauce 6y ago
    > Are they just flat out missing some infections, or do they require a much higher viral load to indicate positive? they do require a higher viral load than the pcr test to accurately show infection. the pcr test studies have shown to be 0-30% false negative later in the illness after symptoms have shown (when there are fewer antigens in the body). both the pcr and the rapid tests are expected to have a near 0% false positive rate though with most false positives being lab contamination or mishandling. even if the test is 50% false negative(not the actual number) it would still drastically slow the spread of the virus coupled with other measures. This is more of a defense in depth instead of a firewall; the swiss cheese layers of threat reduction.
- whimsicalism 6y ago
  Rapid tests are just a gamble if you want to save time/money/exposing others if you end up being positive. If you're negative, you then have to get the actual test, but if you're positive you can probably start isolating now.
  - nip180 6y ago
    > if you’re positive you can probably start isolating now. If you experience symptoms you should start isolating, regardless of the results of a rapid test.
    - midasuni 6y ago
      It’s the people without symptoms. Doing a regular test every few days will prevent at least some spreading if you are a symptomless carrier

pvarangot 6y ago

Thanks for your anecdote. When SF was doing better and the possibility of big outdoor events with testing on the door were something that was being discussed, I looked at rapid tests together with some friends and the accuracy is really appalling. People relying on this to "safety socialize" may be one of the issues making cases rise in California, the math adds up. Many people reached to the government saying they should stop sponsoring and advertising rapid test sites because the false sense of security may be really doing more harm than good. One of the rapid tests that we considered has, as advertised by its own manufacturer, a 10% false positive rate on basically all the population, and a 50% false negative rate even on symptomatic individuals with high viral load. Do the math, but using that type of test in something like for example a 100 person event or a restaurant will result in people being turned out of the door daily even if they were not symptomatic, and at least one or two people with high viral load being admitted into your place. I can't find the link of the test now, but there's better data about how harmful rapid tests are when not used together with PCR testing, for example here: https://www.bmj.com/content/371/bmj.m4941 https://www.bmj.com/content/371/bmj.m4941 and here: https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Sensitivity-Is-Not-the-Whole-St https://asm.org/Articles/2020/November/SARS-CoV-2-Testing-Se... That's why most countries that really thought this through require a recent PCR test result for admittance. It's really not clear what benefits rapid tests have if you don't have a model for population behavior. I think at lest the SF government is only doing them to save face now that the cat is out of the bag.

jonny_eh 6y ago

I hope you get well soon!

DeRock 6y ago

Whether a test is positive or not depends highly on what type of test it is, and when you are tested relative to symptom onset. You can absolutely be carrying the COVID virus but still test negative. Heres a paper with a handy chart: https://jamanetwork.com/journals/jama/fullarticle/2765837 https://jamanetwork.com/journals/jama/fullarticle/2765837 I think you testing negative was a combination of the rapid test being unreliable, as well as getting tested early with respect to symptoms.

jedberg 6y ago

This rapid tests have a very high false negative rate. The result you get back should really be "You have COVID" or "You may have COVID, get a PCR test".

graeme 6y ago

Rapid tests are at their most accurate when someone is at their peak infectiousness. Accuracy declines swiftly before or after that. So the use you made of them didn’t fit their ideal use case, as you used them several days before travel. Even then, with symptoms, I am not sure they would be enough to rule out a positive. The biggest use of rapid tests is finding additional positives that would not otherwise have been found.

situationista 6y ago

Most countries which require a test for entry stipulate it must be a PCR test rather than a rapid (antigen) test. I’m currently in Lisbon waiting for the results of a 24h PCR test in order to board a flight to Azores, for example.

option 6y ago

note that rapid test is still useful to confirm infection. But, yes, much more unstable for ruling out one

Osmium 6y ago

I'm glad the OP made the correct decision in this case and hope they get well soon. > the assumption I had a minor cold > the loss of smell was total Since there does seem to be a messaging problem about the reliability of testing, I think it's worth emphasizing: if someone has symptoms of COVID, they should proceed as-if they have COVID. CDC guidance[1] is to isolate if you have a positive test OR if you have symptoms. To do otherwise is to gamble with the health and lives of the people they meet, and the people those people meet, and so on. It may prove almost impossible to show who caught COVID from whom, but that doesn't mean that ignoring guidance won't lead to deaths. A statistical death is still the death of a real person, even if we can't put a name to them. [1] https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/isolation.html https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/is...

nilkn 6y ago
To be clear, the order of events was such that I did not have loss of smell/taste at the time of the rapid tests. There was no indication at that time of anything that wasn't completely consistent with and expected from a cold, and I even encountered resistance when I tried to get tested prior to the tell-tale loss-of-smell symptom appearing (hence the rapid tests only at that point). I had a mildly uncomfortable phone call with an urgent care center where they discouraged me from pursuing testing because they didn't think I had enough symptoms. I knew exactly from whom I had contracted whatever illness I had, and that person had also tested negative for COVID (upon further questioning, their test had also been a rapid one, and they too had not been informed of its unreliability for any negative determination).
- bigiain 6y ago
  > There was no indication at that time of anything that wasn't completely consistent with and expected from a cold Unfortunately, I think these days symptoms of "just a cold" are enough reason to self isolate for long enough to reliably get through the Covid incubation period - which locally (Sydney .au) has been reported to occasionally be as long as 10 days or more.
  - 6y ago

koyote 6y ago

> A week later, the positive test result came back Which country do you live in that it takes a week for the PCR test to come back? It's around 24 hours here and I thought that was the case in all developed countries. I hope you recover quickly!

nilkn 6y ago
I'm in the US. The test was taken on a Sunday evening at about 7:30PM, and the results were delivered via text message the morning of the following Friday. My guess is there's a lot of variability in how long it takes to get results. I know folks who've taken the same test and they got results back within 48 hours.
- zo1 6y ago
  South Africa here. I've known people that got their test back in less than 24 hours
  - markus92 6y ago
    Netherlands here, I routinely get them back within 8 hours after taking the swab. At work (hospital), we can get them within an hour if it's urgent.
- kelnos 6y ago
  There's a lot of variability, and it depends on how far you are from the lab the particular test center uses, how quickly the test center sends your sample to the lab, and how busy the lab is. I've had two tests that came back in around 48 hours and one that only took 8 hours (US, SF bay area). 4.5 days seems pretty excessive (and frankly pretty useless) though!
bigiain 6y ago
> Which country do you live in that it takes a week for the PCR test to come back? I'd guess a country with a totally dysfunctional, practically 3rd world medical system, with deeply entrenched profiteering and usury. So most likely the USA?

glandium 6y ago

Note that even PCR tests have a relatively high rate of false negatives.

arcticbull 6y ago

If you still have yet to test positive for COVID you may not have COVID. A loss of sense of smell and taste is a common symptom of a viral infection.˜ [1] [1] https://www.healthline.com/health/coronavirus-loss-of-taste-loss-of-smell#an-early-symptom https://www.healthline.com/health/coronavirus-loss-of-taste-...

bigiain 6y ago
Yeah - so you should probably go to a political rally or concert or a nightclub or something!!! :sigh: This is awful advice for 2021. (Even though _technically_ it's correct.) If you have a loss of smell/taste you should 100% assume you have Covid and act accordingly, get tested immediately, self quarantine for probably 14 whole days, and get retested at around 10 days. If you have "mild cold/flu symptoms" you should assume you like;y have covid, and should get tested (not with a "rapid test") and self isolate until you get a negative result. Truth is, even with no symptoms, you could have Covid. If you've been in contact with anyone who has cold/flu symptoms, or been to a place where someone with a positive covid test has been - you should get tested (and probably self isolate until you get a negative result). From: https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2774707 https://jamanetwork.com/journals/jamanetworkopen/fullarticle... Results: The baseline assumptions for the model were that peak infectiousness occurred at the median of symptom onset and that 30% of individuals with infection never develop symptoms and are 75% as infectious as those who do develop symptoms. Combined, these baseline assumptions imply that persons with infection who never develop symptoms may account for approximately 24% of all transmission. In this base case, 59% of all transmission came from asymptomatic transmission, comprising 35% from presymptomatic individuals and 24% from individuals who never develop symptoms. Under a broad range of values for each of these assumptions, at least 50% of new SARS-CoV-2 infections was estimated to have originated from exposure to individuals with infection but without symptoms. Conclusions and Relevance: In this decision analytical model of multiple scenarios of proportions of asymptomatic individuals with COVID-19 and infectious periods, transmission from asymptomatic individuals was estimated to account for more than half of all transmissions. In addition to identification and isolation of persons with symptomatic COVID-19, effective control of spread will require reducing the risk of transmission from people with infection who do not have symptoms. These findings suggest that measures such as wearing masks, hand hygiene, social distancing, and strategic testing of people who are not ill will be foundational to slowing the spread of COVID-19 until safe and effective vaccines are available and widely used.

devy 6y ago

> But if the rapid tests are as unreliable in general as they were for me, it’s sort of no wonder COVID is spreading like wildfire. Many rapid tests are indeed not accurate[1] but they still serve a purpose, depending on the sensitivity and specificity of the tests[2]. For the rapid tests with high sensitivity and you get a positive result, it's highly likely you have COVID. For the rapid tests with high specificity and you get a negative result, it's highly likely that you don't have COVID. And the public health measures of testing / contact tracing ONLY works if testing results come back quick. PCR tests are neither fast nor cheap, so those are not as effective in prevention of spreading because you don't do those all the time (slow + expensive). Medcram has a good video talking about this. [3] [1]: https://www.wsls.com/news/local/2021/01/08/cdc-study-shows-covid-19-rapid-tests-not-as-accurate/ https://www.wsls.com/news/local/2021/01/08/cdc-study-shows-c... [2]: https://en.wikipedia.org/wiki/Sensitivity_and_specificity https://en.wikipedia.org/wiki/Sensitivity_and_specificity [3]: https://www.youtube.com/watch?v=h7Sv_pS8MgQ https://www.youtube.com/watch?v=h7Sv_pS8MgQ

kelnos 6y ago
I only have data points for two different testing orgs, but in my area, GoHealth charges $250 for a rapid test, and Color charges $110 for a PCR test[0]. So it seems like that's flipped from what you're suggesting? The Color tests can even come back in 8 hours or so, if you're not too far from a lab and the lab isn't overloaded. Not as fast as 15 minutes, and certainly higher variance, but much more useful than 72 hours people normally assume. Regarding false negative rate, Hawaii is accepting some of the rapid tests (like the aforementioned GoHealth test) for pre-travel screening, which is concerning. [0] These are both without involving insurance at all. It's possible, though, that the Color tests are partially subsidised by Google?
- calvano915 6y ago
  Simply, $250 is a scam given the limitations of that type of test. Its simply a money grab from those unaware. Its been known for months that PCR is the gold standard, and rapid tests are not. Rapid tests are good for surveillance but not diagnosis.

Reason077 6y ago

Rapid tests (aka: Antigen tests, or lateral flow tests) are high specificity, low sensitivity tests. That means they’re biased towards the negative side: they’re unlikely to return false positives, but quite likely to give false negatives. Such tests are useful for epidemiological studies, or for answering the “do I have Covid antibodies?” question. But they’re not a reliable way to actually test for Covid. You need a PCR test for that!

anonytrary 6y ago

If you don't mind, can you please share your age or a ballpark estimate? It seems like you are doing well and just had the minor symptoms.

nilkn 6y ago
Sure, I'm in my early 30s. I do believe I had a pretty mild case all things considered, and I'm pretty much fully recovered at this point but still plan to quarantine for another week. What I experienced was basically indistinguishable from a mild cold except for the loss of smell and taste, which took over a week to show up after the onset of the initial symptom (a fever). While I know loss of smell can happen from non-COVID infections, I can say this is the only time in my life I've had a total loss of all smell and taste. I'm very fortunate that this total loss only persisted for a few days, and at this point based on my subjective experience my smell and taste senses appear to be normal again.

lol768 6y ago

They've been using these lateral flow tests in the UK quite a bit - particularly for university students returning home/to campus (or at least, that was the plan!). But I'm not convinced the data on their effectiveness really supported using the tests in this way: https://twitter.com/deeksj/status/1340975400726478849 https://twitter.com/deeksj/status/1340975400726478849 But it was a political "win".

maxerickson 6y ago

What entity approved the test for distribution?

argonaut 6y ago

There are many different rapid tests. Some are reliable and some are unreliable. For the ones that are reliable (like Abbott's test), they are highly accurate at determining whether someone is currently infectious. So you could have been infected but not capable of transmitting to others yet. These tests would be highly useful for onsite testing, such as if airlines required a rapid test right at the airport.

Tainnor 6y ago

> I have an interesting anecdote related to this. Please don't do that. There is enough knowledge out there about the various kinds of tests (PCR, antibody, antigene) and what they're good for and what they're not. It's perfectly understood that while rapid tests are, well, rapid, they're much less precise than PCR testing. However, they are often better than nothing (you can't give a PCR test to everyone who wants to visit relatives in a nursing home), so they serve to minimise risk, not to remove it. (They also have a tendency to be more likely to be positive while you're actually infectious, which is not the same thing as having symptoms.) I really don't think we should be discussing personal anecdotes during a health crisis, when there's enough data around that we can actually look at.

deleted 6y ago
[deleted]

raxxorrax 6y ago

The most common error with these tests is false application. Did you have someone else doing the swab? It has to feel like someone is poking at your brain.

Technically 6y ago

How is this related to the story? Why waste my time like this? Provide or shut the fuck up—that's how hacker news works for successful assholes.

luisvel88 6y ago

You were probably not contagious during those first days (at least for everyone except your partner).The threshold for the rapid test is higher than what the PCR detects. The antigen test is highly reliable for catching contagiousness, not just any viral load. Michael Mina (Harvard Biologist) presents the data in a great way if you want to check.