South Korea reports recovered Covid-19 patients testing positive again
reuters.com
reuters.com
Kim also said patients had likely “relapsed” rather than been re-infected.
False test results could also be at fault, other experts said, or remnants of the virus could still be in patients’ systems but not be infectious or of danger to the host or others.
“There are different interpretations and many variables,” ...
https://www.questdiagnostics.com/dms/Documents/covid-19/SARS...
"Is this test FDA-approved or cleared?
No. This test is not yet approved or cleared or authorized by the United States Food and Drug Administration (FDA). When there are no FDA-approved or cleared tests available, and other criteria are met, FDA can make tests available under an emergency access mechanism called an Emergency Use Authorization. Quest Diagnostics is working with FDA to obtain Emergency Use Authorization."
And the tests that are authorized for emergency use are not FDA cleared or approved.
"Testing was performed using the cobas(R) SARS-CoV-2 test. This test was developed and its performance characteristics determined by LabCorp Laboratories. This test has not been FDA cleared or approved. This test has been authorized by FDA under an Emergency Use Authorization (EUA). This test is only authorized for the duration of time the declaration that circumstances exist justifying the authorization of the emergency use of in vitro diagnostic tests for detection of SARS-CoV-2 virus and/or diagnosis of COVID-19 infection under section 564(b)(1) of the Act, 21 U.S.C. 360bbb-3(b)(1), unless the authorization is terminated or revoked sooner."
I'm an infectious disease doctor and would like to point out an important factor in diagnosing this infection (and all respiratory pathogens that use nucleic acid probes for specimen collection). This is of particular concern now that China has transitioned to a much more problematic clinical diagnosis based more on clinical symptoms than PCR testing.
While it may seem trivial how a health care worker jams a swab in to someone's throat or nose, technique is important. If anterior naries (front of nose) swabs or side of mouth swabs are done, rather than the true posterior nasopharynx or oropharangeal swabs, the sensitivity drops dramatically.
We have shown this to be true repeatedly with diagnosis of influenza and respiratory pathogens, and I am disappointed that it has not been mentioned more in discussions about the PCR tests, missing the diagnosis in people who are positive and negative then positive again.
We often see people admitted from the ER with the perhaps carelessly collected flu test who miraculously are flu positive by the time they are admitted. Like so many cultures and diagnostics in infectious diseases, specimen collection and handling is critical.
I warn my patients about the unpleasantness of a nasopharangeal swab and jokingly tell them that if it doesn't cause a wincy-face reaction we haven't collected specimens from where the viruses reside.
[1] - http://www.microbe.tv/twiv/twiv-588/; at about 1 hour and 38 minutes in
RT-PCR tests can only test for the presence of viral RNA in the sample collected. They cannot tell you the viability of the viral particles, they cannot tell you if you going to get sicker, or going to get better the next day. We don't even fully understand the relationship between vRNA detection and contagiousness. And all of those unknowns are outside of the scope of the test.
Even in normal times, these tests can only be used to determine if genetic material exists (and sometimes the quantity if the collection mechanism and processing are controlled enough). It must be left up to clinicians to interpret these results.
The current protocol is to wait for 2 consecutive negatives 24 hours apart to call someone virus free. That's a protocol created by clinicians in a time of extreme pressure and need based on empirical measurements and prior body of knowledge.
A 510k cleared COVID test would have most of the same issues because the problem isn't strictly that the tests can't reliability detect viral particles, the problem is that we don't know what actually constitutes "cured".
[1] https://www.wsj.com/articles/questions-about-accuracy-of-cor...
This German study (https://www.medrxiv.org/content/10.1101/2020.03.05.20030502v... -- see the graphs near the end of the PDF) suggests that viral RNA may be detectable in recovered patients for 3 weeks after symptom onset, or longer (the study seemed to stop testing after 3 weeks, despite some recovered patients still testing positive for viral RNA). But they were unable to isolate live virus after about a week post-onset.
Could this be what we're seeing?
If you're still worried, I recommend looking at this small study on macaques designed to test immunity (https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1). They found that the macaques did develop immunity and were able to fight off the virus on reinfection. If we compare with the this study (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/) on the development of immunity in response to the original SARS virus (I'm not sure on the exact mechanism of immunity, but if the body's immunoglobulin response targets the spike protein, then it's probably similar), we should probably expect antibody production to continue at least a year after infection, if not for 3-4 years after.
That or accept the 0.5 percent death rate with the "flatten the curve" method where we all catch it.
Your concern means we'd only have situation 1, quarentine for 1 or 2 years.
Deadly, contagious virus with no vaccine, which takes roughly 18 months. There aren't too many options. I've heard chatter that big co's started telling their employees they're planning 18 months WFH.
Once the disease surge in densely populated ends areas it appears to become quite manageable.
We'll probably wear masks this entire time, and there'll probably another closure next time the disease surges. Until we find an effective treatment or a vaccine.
If there's a second wave, we'll probably need those containment measures again just to bring it down to the flu level.
If this were a raging pandemic this would not be the case.
E. Asian countries use a strict screen-and-test routine (+ a few restrictions), and if/when that slips they turn to a lockdown until they can control the outbreak enough to return to screen-and-test (e.g. Singapore just these recent days). That's a data point, but I don't think it supports the 'just get back to usual' POV. The US has far more entry points than Singapore, even after it manages to control the disease internally.
The UK abandoned their no-lockdown policy because it didn't work.
That leaves us with.. Sweden which doesn't look good at all compared to its neighbours which have locked down?
Honest question: do you think a second quarantine will be as effective as the first? Tracing and isolation after the first quarantine must be as close as spotless as possible, because personally I don't believe that the population will tolerate a second lock-up as easily as the first.
Public will may decline/increase depending on country and political climate, but enforcement, tracking and treatment mechanisms will have improved everywhere. So a 2nd quarantine need not be as effective as the first, and overall, governments that will want to lock down will be able to do it.
The real question is whether a political/economical calculation will delay a 2nd quarantine unnecessarily in cases it is necessary.
[0] https://www.theguardian.com/world/2020/apr/01/singing-stops-...
Governments and their expert panels can't just think that people will "reprogram" themselves to stay away from most social contacts. It's alienating at best and outright dangerous for one's mind at worst.
Once the number of cases gets low, it won't be possible, or justifiable, to keep people locked up. Even more so that some countries that were affected after my own have already begun their plans to lift lockdowns (some with definite dates, some without).
It's not like somewhere like China got to lower numbers now because most of them got it and are immune. As percentage of population the number that got it is quite small. They got control of the situation because the people who had it didn't spread and they recovered. Now they are vulnerable to it being reintroduced. But they don't need full lockdown.
So another scenario is that active cases subside and we don't travel or amass in large groups for a while. This is short of your two year quarantine (which by the way you didn't spell correctly, a hint for how to spell it is that it derives from Italian 'quaranta', meaning 40, for a 40 day isolation).
This is unfeasible for most of the population, and a vaccine may not work at all (people assume it will, but there's no guarantee). If they work, drugs are what will be needed to turn the tide short-term.
They feed off each other.
And HN isn't entirely immune. I see some of it happening here too, though it is not as prevalent as on Reddit.
Also, look at the argument, not the user. You have appeal to authority fallacy.
The reason is that people are far too quick to leap to this interpretation, and since we have next to no data about each other from HN posts, pretty much every divisive topic gets drowned in such insinuations if allowed to.
Lots more explanation here: https://hn.algolia.com/?sort=byDate&dateRange=all&type=comme...
* Mandatory mask usage
* Mandatory temperature checks in certain places (restaurants, airports, etc?)
* Many companies continuing their WFH policies
* Greatly expanded testing and contact tracing, allowing local outbreaks to be more easily contained
* Quarantines for high risk individuals
If, however, it's the absolute worst case scenario that we don't get any immunity after infection and thus a vaccine is useless, then basically there's nothing we can do except build more hospitals and research treatments that prevent death. We would probably have to live a very different life going forward, ie. wearing masks all the time and other changes.
In such a worst case scenario, at some point I would think our ability to detect the virus would become almost instantaneous, so we can have scanners/detectors at every entrance to allow for immediate detection and immediate quarantine. That would probably help keep the spread down immensely.
Having read the reports on the government's initial modelling, it still seems like they're sticking to their initial plan. They recommended enacting social distancing and lockdown measures to keep the infection rate manageable for the NHS, relaxing and tightening the measures to keep the spread at the maximum sustainable rate. Lockdown hasn't been relaxed as the infection rate still hasn't started going down, but their initial 'review in 3 weeks' was based on the incubation period, as they expected to see a slowdown after 3 weeks.
The advice said explicitly that social distancing measures would need to be in place for `at least most of a year` and the strictest restrictions would need to be in place for about 6 months.
That explains why the UK is still refusing to close businesses, and just recommending that you work from home where possible. While other countries are attempting to stop the spread completely, the UK is trying to keep it at a manageable level.
Their judgement is that it's impossible to control this virus unless most of the population is immune, and that it's also impossible to irradicate it through social distancing and lockdown. The only solutions therefore are to stay in lockdown until a vaccine is developed, or let 70% of the population get infected and become naturally immune. They don't think a 12-18 month lockdown is feasible, so they are going for option 2.
Within that goal, they are trying to minimise the death toll:
* make sure that the 70% infected are young and healthy, with over 70 and anyone at increased risk quarantined inside their homes for 4 months
* Keep the infection rate low enough that the NHS is within capacity meaning a mortality rate of ~1% instead of ~5%
* Give up on mass testing and containment, asking people to isolate once they notice symptoms - they want people to spread it
I know you were just making an abstract point and agree that if it were possible it would work but unfortunately people are not livestock. If you are a religious person consider the fact that even god can't or wont take away the free will of men, wiping everyone out with a flood or plague seems more doable.
There's viruses that go dormant and become invisible to your immune system like how Herpes viruses go dormant in your nervous system, and there's viruses that get into your DNA like HIV and then are pretty much impossible to get rid of without getting rid of all of your cells.
Coronaviruses don't do either of these things.
The US will be forced to live with the herd immunity strategy, but they won’t call it that.
The final mortality of Covid is likely to be lower than the flu according to the latest CDC projections (60K vs. 80k flu last season). Not scary enough for forced vaccinations.
It's not a joke, we are only 3 months into looking at the virus, we can't be sure what it's doing.
What is happening here? We started to see this a month ago in Japan.
Given every step so far in all countries leaders have shown no understanding of even the obvious and what to do, I think they are just choosing to ignore it at our peril.
Although I think it is doubtful, if it does end up killing 10-20% like the Spanish Flu then better to get it over with instead of stretching it out. The good news is that after the Spanish Flu we had the roaring 20’s so there is still light on the horizon.
> The South Korean figure had risen from 51 such cases on Monday.
> "The number will only increase, 91 is just the beginning now"
You can just think of booster immunizations and getting tetanus shots when you're exposed. Why would you need those, otherwise? If you want to learn more looking into memory T and B cells.