[HN Gopher] Ten-Minute Coronavirus Test for $1 Could Be Game Cha...
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Ten-Minute Coronavirus Test for $1 Could Be Game Changer
Author : montalbano
Score : 312 points
Date : 2020-03-16 17:16 UTC (5 hours ago)
(HTM) web link (www.bloomberg.com)
(TXT) w3m dump (www.bloomberg.com)
| the_arun wrote:
| In the same lines - Apple Watch or Samsung watch sensing it
| through sensors would be so cool. I'm not a doc, so don't know
| the practicality of it
| nomel wrote:
| They have some LEDs that shine light into your skin. You're not
| detecting a specific pathogen by shining UR and visible lights.
| boomboomsubban wrote:
| What is enabling them to be the only people able to develop this
| far better test? Is the rest of the world unaware how home
| pregnancy and malaria tests work?
|
| If this was worth reporting on, there should be some kind of data
| showing how effective and cheap the test is when compared to the
| competition. I wonder what led Bloimberg and other financial news
| to pick this story up.
| pmoriarty wrote:
| _" What is enabling them to be the only people able to develop
| this far better test?"_
|
| They're far from the only ones who've developed a far better
| test.
|
| Without specifically looking for them, since the outbreak began
| I've seen 4 or 5 reports of different companies developing far
| better tests.
|
| Unfortunately, I don't know if any of them have actually been
| put in to use, or what the obstacles to doing so are.
| giarc wrote:
| If you are a company that wants to sell a test, you will
| definitely say it's a "far better test". Whether it actually
| is a better test is a much different story.
| VectorLock wrote:
| I think the biggest obstacle is actually doing the testing of
| the tests to see if they're far better. Putting an
| ineffective or highly false positive/negative test out there
| could do more harm than good.
| boomboomsubban wrote:
| >I've seen 4 or 5 reports of different companies developing
| far better tests.
|
| Were any of the reports more detailed than "hey, we developed
| a better test. Give us money."
| baq wrote:
| it's either that and containment South Korea style or total
| lockdown China style. too much risk to be in between, though some
| were trying.
| uptown wrote:
| Assuming tests aren't available -- is there nay prescribed care
| one can provide to others or do for ones-self if they contract
| the virus? I realize some conditions may worsen to the point that
| you'd require medical attention --- but what's the best course of
| action assuming that professional care is unavailable?
| fma wrote:
| I feel like a question like this is better served doing a
| Google search and finding results from reputable
| sources...rather than asking a question on HN.
|
| Having said that, Coronavirus is consider a repository
| illness...so you'd probably perform the same home treatment as
| any other respiratory illness.
| rory096 wrote:
| >you'd probably perform the same home treatment as any other
| respiratory illness.
|
| Notably, you should not take ibuprofen or other NSAIDS. Stick
| to acetaminophen/paracetamol instead.
|
| Guidance from France's health minister:
|
| https://www.theguardian.com/world/2020/mar/14/anti-
| inflammat...
|
| https://twitter.com/olivierveran/status/1238776545398923264
| swebs wrote:
| https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/st...
|
| https://www.cdc.gov/coronavirus/2019-ncov/if-you-are-sick/ca...
| asiachick wrote:
| $1 would be nice. Some company in Japan is selling kits $250 for
| a 10 test kit
|
| https://monoist.atmarkit.co.jp/mn/articles/2003/13/news055.h...
|
| Google Translate Translation
|
| https://translate.google.com/translate?sl=auto&tl=en&u=https...
| bugzz wrote:
| Why are flu tests so much slower and more expensive?
| shard wrote:
| I'm sure the are different types of flu tests, but the last one
| I had at the doctor's office about 2 years ago was two swabs of
| my nose, which the doctor put into a test kit, and a few
| minutes' wait for the results to develop in the kit. No idea
| how much it cost, though.
| kube-system wrote:
| Probably because "the flu" is hundreds of different viruses and
| the entire world is not currently dumping massive amounts of
| resources behind developing them.
|
| Then again, the rapid flu test only takes about 5 to 20 more
| minutes than this, and doesn't really cost much more than any
| routine diagnostic.
| guitarbill wrote:
| > test for the virus in Nigeria, Africa's most populous nation,
| with about 200 million people.
|
| > its saliva and finger-prick kit could be ready for sale by June
| for less than $1 apiece
|
| > Mologic and the Institut Pasteur have joint capacity to produce
| 8 million tests a year
|
| every little helps, and a low-cost test would obviously be a
| game-changer. but let's keep things in perspective and be
| realistic. it sounds quite hypothetical right now. there's no
| indication it works reliably yet.
| mars4rp wrote:
| Decision Diagnostic a blood sugar test developer company is
| developing a handheld device and the cost of each test would be
| less than $7. They are hoping to deploy 200K unit by May.
| https://finance.yahoo.com/news/decn-updates-corona-virus-tes...
| Rapzid wrote:
| We are royally screwed if this thing hasn't played out by June.
| ohazi wrote:
| I really don't see how anyone expects this to be over by
| June.
|
| Exponential growth at the current rate would have it burning
| through the global population by the end of June, but since
| exponential growth becomes logistic growth after an
| appreciable fraction of the population is infected, June is
| probably closer to the halfway point than the end date.
|
| And that's assuming zero curve flattening. The entire point
| of flattening the curve is to draw it out so that hospitals
| continue to function for longer. But this also makes the
| pandemic last longer.
|
| A vaccine isn't expected for over a year, and even then, I'd
| expect at least a few months of logistical difficulties
| getting enough manufactured, distributed, and administered,
| especially given the state that hospitals will likely be in.
| Rapzid wrote:
| Yes, this was what I had in mind when I made this comment.
|
| We would be screwed, IMHO, based on the current mitigation
| strategies around curve flattening that are not being
| communicated realistically to the public. The crop of
| shutdowns over the weekend were billed as 2-3 weeks.. Err,
| what? How are we even going to know what effect that's
| having without massive blanket testing? Then, nobody seems
| to believe anything less than 8 weeks is enough; and that's
| full-blown lock-down not fractions of half measures.
|
| But as you say, the just spreads it out. So what happens in
| 8 weeks when we still can't let up the restrictions because
| if we did that the number of cases would just explode again
| among the uninfected population? If we aren't turning the
| corner by June and getting the 40% of adults who can't
| afford $400 in an emergency back to work..
|
| I'm sympathetic to the UKs strategy and hope the best for
| them.
| ohazi wrote:
| > The crop of shutdowns over the weekend were billed as
| 2-3 weeks.. Err, what?
|
| Exactly. People seem to be mistaking the incubation
| period (~two weeks) for the length of time the pandemic
| will last (months at minimum).
|
| It's impossible to have a perfect quarantine, so if we
| were to all go back to normal after a month, the pandemic
| growth curve will pick up where it left off. Exiting the
| lockdown will need to be done super carefully to avoid
| this outcome.
|
| As far as I can tell, this is probably going to be the
| new normal until we have a vaccine.
| mobilefriendly wrote:
| The 40%/$400 item comes from a fed survey about
| liquidity. It includes 17% of households with $100,000 in
| income. It is an outlier, other surveys put it the
| percentage at 20%.
| Darkphibre wrote:
| Not sure why your score is so slow, you're spot-on. This is
| _literally_ the global pandemic we 've been scared of. It
| just came out of China instead of the Democratic Republic
| of Congo.
| ajuc wrote:
| Economy is screwed either way, but for the people it would be
| better if it goes slowly - then our healthcare systems can
| deal with it.
|
| If it just goes unchecked exponentialy for 2 months then
| significant fraction of world population will die. Like
| 2-digit percentage.
| zabana wrote:
| How so ? Care to elaborate ?
| notahacker wrote:
| A lot of people will have died and our economies really
| aren't built for long term social isolation either.
| [deleted]
| empath75 wrote:
| actually we're more screwed if it has -- that means it would
| have burned out world wide in 6 months and 10s of millions
| would have died.
| ehsankia wrote:
| Depends how much we're able to slow it down. For example
| Canada had first case in January, and 2 months later is only
| up to ~500 confirmed cases. It is still exponential but much
| slower. Hopefully the new measures put in the past week will
| slow it even more.
|
| At which point, once we have fast and reliable testing, we
| can actually start having people go out more and reduce the
| isolation, since we can count on better testing to stop the
| spread.
| greenshackle2 wrote:
| In Canada, growth was slower for a while, but the number of
| (detected) cases has doubled twice in the past 5 days,
| which just about matches what we saw in Italy and the US
| once they hit 100 cases.
| r00fus wrote:
| Sounds like what happens when one of the criteria to get
| tested (which is expensive) is "having been in presence
| of known existing COVID-19 case".
|
| It's a symptom of massive under-testing and would be
| greatly alleviated by an inexpensive test.
| btilly wrote:
| _For example Canada had first case in January, and 2 months
| later is only up to ~500 confirmed cases._
|
| My niece and great nephews in Victoria, BC just turned up
| with symptoms for COVID. They were told to self-quarantine
| and were not tested.
|
| You cannot believe the numbers from any country which does
| not have a robust testing regime. That emphatically
| includes Canada along with the USA.
| jopsen wrote:
| Yeah, in Denmark yesterday simple math says that 18% of
| people tested was infected.
|
| That's not to suggest that 18% of the population is
| infected. Merely suggests that positive tests is a
| useless metric because people are not tested.
|
| Number of people admitted to hospital might be a better
| indicator -- though this has a lot of delay.
| blhack wrote:
| In the White House press conference today, the head of the
| NIAID said don't expect things to return to normal until July
| or August.
| slowhand09 wrote:
| "masks and test kits". Epidemiologists say masks are
| practically useless against virus. The one that is effective
| with special training is useless without.
| christkv wrote:
| It takes you 5 min to learn how to put on and take off a n95
| mask correctly. Even if you do it wrong you are still
| protecting other people against your potential infection.
| pbhjpbhj wrote:
| Hmm, I think NHS courses last longer than that. The mask
| makers sell a [very expensive!] testing kit you can use to
| check the mask is fitted too, I gather.
| christkv wrote:
| According to Singapore Health
| https://www.youtube.com/watch?v=zoxpvDVo_NI
| 13415 wrote:
| If they were practically useless, then health care workers
| wouldn't use them...
| Merg wrote:
| Surgical high-proof mask doctors and nurses use are pretty
| good against viruses, combined with googles of course.
|
| For normal person? They are mostly useless. Only for
| people, who are already sick, to stop them from spreading
| virus further. Wearing mask by healthy person doesn't make
| sense, because there is not much to stop viruses with
| coming in contact with your eyes. You are always a scratch
| away from bringing those viruses into your body, negating
| any benefit from mask. And most of mask, you can buy
| currently are not dense enough to capture viruses.
|
| OP is correct, unless you are sick or medical worker, you
| don't need mask. Don't buy them, hospitals need them much
| more than you.
|
| Is WHO [1] good enough source for you?
|
| [1] https://www.who.int/emergencies/diseases/novel-
| coronavirus-2...
| 13415 wrote:
| I believe this is primarily a narrative that was invented
| to prevent a temporary shortage of masks for health care
| workers. This may be a noble cause, but it's still a lie.
| Surgical masks reduce the probability of infecting others
| if you have it (maybe without knowing), and correctly
| used N95 masks drastically reduce the risk of getting
| infected.
|
| There is a reason why South Korea officially distributes
| masks to the public. Everybody in China and Japan wears
| masks, too.
| lukaslalinsky wrote:
| The thing with this virus, you typically don't know you
| are infected until it's too late and you already infected
| a number of others. The goal with masks is not to protect
| you, but to protect the general population. Any basic
| mask will do for that purpose.
| pbhjpbhj wrote:
| Surely that's why it was crazy when ordinary, uninfected
| people, wanted to wear masks to tell them "well that
| won't help".
|
| I can't see how reducing transmission "isn't helping".
| mulmen wrote:
| Because masks don't reduce transmission. Communication on
| this has been very clear. Masks don't help. Frequently
| washing hands, avoiding contact with others, keeping your
| surroundings clean, and not touching your face does help.
| Masks give a false sense of security and reduce supply
| for those that need them.
| vl wrote:
| I wonder why in China and Korea, in counties most
| experienced in current situation, everyone is required to
| use them.
| watwut wrote:
| I wonder why doctors and nurses use them then. They usw
| them in most situations. I wonder why they complain about
| lack of them. Since they are useless.
|
| Sure, they are not as good as respirators. And we as
| general public should not bulk buy them now.
| kazinator wrote:
| The source doesn't substantiate anything you wrote in
| your comment.
|
| They say "If you are healthy, you only need to wear a
| mask if you are taking care of a person with suspected
| 2019-nCoV infection."
|
| That assumes you're doing everything else to protect
| yourself already, like stay away from crowded places.
|
| It also assumes that _you know that you 're healthy_. You
| could be carrying COVID-19 without knowing it!
|
| One reason health practitioners wear masks is not to
| infect vulnerable patients with something they might be
| carrying.
|
| > _there is not much to stop viruses with coming in
| contact with your eyes._
|
| Other than the goggles that you mentioned; yet, nurses in
| hospitals don't routinely wear goggles, yet do wear
| masks.
|
| This is probably because your eyes do not suck in air the
| way your air passages do, and also don't spew viruses
| into the air.
| watwut wrote:
| > Surgical high-proof mask doctors and nurses use are
| pretty good against viruses, combined with googles of
| course.
|
| Maybe my country is outlier, but doctors in non surgical
| situation use mask (not respirator) and no googles. It is
| not airtight either.
|
| I don't think they do it because it would be useless.
| pbhjpbhj wrote:
| >They are mostly useless. Only for people, who are
| already sick, to stop them from spreading virus further.
| //
|
| Um, this is kinda what ordinary people want!!
|
| If you stop it spreading, then most of us don't get it!
|
| Yes, it doesn't stop you getting it, but if it stops you
| spreading it then we hinder/stop the epidemic [but we're
| way past that now].
| pbhjpbhj wrote:
| > Epidemiologists say masks are practically useless against
| virus. //
|
| Have you seen any of them cite a research paper showing that?
| I haven't, I'm open to suggestions if anyone has one.
|
| Same thing with the "keeping schools open won't spread the
| virus" thing in the UK; lots of establishment scientists
| saying "trust us" but a dearth of papers detailing how the
| established beliefs are wrong that schools are prime
| transmission vectors for ARI (and closing them has helped to
| hinder influenza trasmissions in the past).
|
| Not being snarky; if you've got backing for "masks don't
| hinder viral spread" then lets see it.
| ColanR wrote:
| In general, masks are something that the sick person wears
| to prevent germ spread. Same idea as why surgeons wear them
| in the operating theater.
|
| The only kind of mask that's going to filter particulate
| matter out of the air (i.e., be effective against the virus
| for someone who is not infected) is something that has an
| airtight seal.
| KptMarchewa wrote:
| Epidemiologists say to stop buying masks only because there
| are not enough of them for the healthcare system and general
| population.
| schuke wrote:
| I thought it's more like there's no evidence that show
| massive use of masks by the public is effective.
| jacobolus wrote:
| https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/
| "Any type of general mask use is likely to decrease viral
| exposure and infection risk on a population level, in
| spite of imperfect fit and imperfect adherence, personal
| respirators providing most protection. Masks worn by
| patients may not offer as great a degree of protection
| against aerosol transmission."
|
| https://www.ncbi.nlm.nih.gov/pubmed/19193267 "We found
| that adherence to mask use significantly reduced the risk
| for ILI-associated infection"
|
| https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858
| .CD... "Surgical masks or N95 respirators were the most
| consistent and comprehensive [physical intervention]
| supportive measures."
| TallGuyShort wrote:
| It's complicated. It doesn't stop you from getting the
| virus if you get droplets on your hands and rub your eyes
| / nose / mouth, which is one of the more common vectors.
| So I buy that there's no evidence it stops you from
| getting the disease. But it does limit the droplets you
| spray out as you're speaking / coughing, etc. So IMO it
| would be part of a general solution to limit how much you
| spread the disease. But self-quarantine is easier to be
| sure you're doing it right. Wearing N-95 masks
| effectively is harder than just strapping it on, and the
| untrained are likely to touch their faces more while
| they're doing so anyway. I'd be surprised if everyone
| wearing a fresh mask properly and washing their hands
| properly before touching the mask or face didn't put a
| major dent in the pandemic. But that's just not going to
| happen anyway so we can't tell.
|
| I think the big issue is supply for medical staff.
| There's a limited supply of legit masks. Medical staff
| need masks more. We need medical staff more. And the
| masks are more effective with training / other procedures
| in place. Other than that - if the masks didn't help you,
| medical staff wouldn't wear them.
| ehsankia wrote:
| This is the right answer. As someone who has the virus,
| it absolutely helps you not spread it. As someone who
| doesn't, it may stop a few droplets from getting into
| your system right at that moment, but said droplets can
| still get on your hands, and 30m later when you scratch
| your nose, you'll still get infected.
|
| So yes, with supply being low, it's far more useful for
| infected people to not spread said droplets.
| solinent wrote:
| Exactly: put quite simply the best mitigation measure is
| a mask, since it prevents most of the virus from getting
| into the air--the virus's primary medium of transmission.
| bawolff wrote:
| I thought it was more, they are ineffective because most
| people put them on wrong.
| rconti wrote:
| I hate to sound anti-science, but with something "spread
| by droplets" from coughs and sneezes and spit, where we
| should avoid touching our faces, it sure as hell sounds
| like even the most basic mask could be hugely helpful.
|
| They're trying to conserve masks for health care
| professionals, and DEFINITELY don't want people using
| "I'm wearing a mask" as an excuse to go out when they
| should just stay home, but I can't imagine they don't
| help a lot.
| watwut wrote:
| It is the black and white thinking. The mask is either
| useless or perfect. The case where it would lower
| probability is considered "useless" cause it is not
| "perfect".
|
| Imo, this all or nothing thinking is contemporary issue
| that plays out in many contexts and we collectivelly
| really should get out of it.
| A-Train wrote:
| There is evidence look at Asia. Everyone is wearing a
| mask and they control the virus. If you want to search
| for research based evidence there are plenty but focus on
| the research pre coronavirus - right now there is too
| much noise. One research suggested that with good
| handwashing masks reduce the infection rate by 75%.
| entee wrote:
| N95 respirators have a pore size on the order of 100-300
| nm. Viral particles can be a lot smaller than that
| (5-10nm), but this coronavirus seems to have a 80-90nm
| diameter. That means a respirator _might_ be able to stop
| the particles IF worn perfectly (if you have stubble or a
| beard, you 're already screwed). They will however stop
| droplets from someone sneezing or coughing, again IF worn
| properly. Medical professionals get fitted regularly to
| ensure proper fit.
|
| Masks are only effective in a fairly immediate radius:
| someone coughs, that droplet goes a little ways then
| falls on a surface. Medical professionals are in that
| immediate radius all the time, that's why they need the
| masks. People are usually not sneezing directly on each
| other, so that's less of an issue. What IS an issue is
| the viral particle that is now on a surface. You touch
| that, move your hand to your face (perhaps to adjust your
| mask) and bingo you're infected. Washing your hands
| obsessively is WAY more useful than any mask.
|
| Most of the time in medicine masks are used to stop the
| medical professional from contaminating the patient, not
| the other way around (that's what you see in surgery). If
| you're with someone sick, it would be good to give them a
| mask, they'll spread fewer particles that way.
|
| TLDR: Masks are minimally useful for the broader public,
| very useful for those directly in harm's way. Don't buy
| masks unless you're sick, or someone close to you is
| sick. Let the supply chain work for medical professionals
| who actually need them.
| DanBC wrote:
| But they do also say that masks are difficult for people to
| use correctly, and if you're not using it correctly it'll
| increase your risk.
|
| slowhand09 has been unfairly downvoted, because they are
| factually correct. Epidemiologists are telling the public
| not to use masks because PPE needs training.
| srcmap wrote:
| Western countries need to spend more energy on mask
| productions.
|
| I heard the mask production automation lines cost $50K to
| $100 in China and TW. Now the price for machines and
| production materials are 5-10 times the normal.
|
| But once setup, 95% - 99% of the process is automated.
| There are zero pollution and it is neither labor nor
| capital intensive. Do need the logistic and abilities to
| source some raw materials. If setup, the next few months
| would be like printing $$$$.
|
| TW can make 10 millions masks per day now. China has
| production line making 110 millions mask per day. They were
| able mobilized the industries like war time - TW actually
| send enlist Army personnels to the factory to help out.
| ixwt wrote:
| Would it be a bad idea for the government to have a
| reserve for healthcare workers for the next time this
| happens? To slowly sell off what is there, and to restock
| to create a buffer. And in a time of crisis, have a large
| amount that can only be bought by healthcare workers.
| theseadroid wrote:
| Yup. In mainland China they repurposed car assembly lines
| to mask production (there's not much car selling anyway).
| Western countries need to copy at least some of those
| measures.
| _jal wrote:
| In general the switch to just-in-time for everything was
| a fair-weather decision. You goose can your margins when
| things are great, too bad about your supply chain when
| things are less than great.
|
| This is probably OK for ice cream and computer hardware.
| Less so for medical supplies.
| lm28469 wrote:
| They say that so we, the dumb animals, don't stockpile them
| like we do with toilet paper (can't find any for 2 weeks
| straight in my area of Berlin for example).
|
| Of course masks are useful, but they're more useful in
| hospitals / on health care workers' face, than on the average
| citizen which won't be in contact with the virus that much
| now that most of the world is starting to get locked down
| anyway
| throwaway894345 wrote:
| Citation please? This seems like overt misinformation.
| ProZsolt wrote:
| They don't say it useless. They just don't recommend it.
|
| https://www.cdc.gov/coronavirus/2019-ncov/faq.html#protect
|
| CDC does not recommend that people who are well wear a
| facemask to protect themselves from respiratory illnesses,
| including COVID-19. You should only wear a mask if a
| healthcare professional recommends it. A facemask should be
| used by people who have COVID-19 and are showing symptoms.
| This is to protect others from the risk of getting
| infected. The use of facemasks also is crucial for health
| workers and other people who are taking care of someone
| infected with COVID-19 in close settings (at home or in a
| health care facility).
|
| Only wear a mask if you are ill with COVID-19 symptoms
| (especially coughing) or looking after someone who may have
| COVID-19. Disposable face mask can only be used once. If
| you are not ill or looking after someone who is ill then
| you are wasting a mask. There is a world-wide shortage of
| masks, so WHO urges people to use masks wisely.
|
| WHO advises rational use of medical masks to avoid
| unnecessary wastage of precious resources and mis-use of
| masks (see Advice on the use of masks).
|
| The most effective ways to protect yourself and others
| against COVID-19 are to frequently clean your hands, cover
| your cough with the bend of elbow or tissue and maintain a
| distance of at least 1 meter (3 feet) from people who are
| coughing or sneezing. See basic protective measures against
| the new coronavirus for more information.
|
| https://www.who.int/news-room/q-a-detail/q-a-coronaviruses
|
| Only wear a mask if you are ill with COVID-19 symptoms
| (especially coughing) or looking after someone who may have
| COVID-19. Disposable face mask can only be used once. If
| you are not ill or looking after someone who is ill then
| you are wasting a mask. There is a world-wide shortage of
| masks, so WHO urges people to use masks wisely.
|
| WHO advises rational use of medical masks to avoid
| unnecessary wastage of precious resources and mis-use of
| masks (see Advice on the use of masks).
|
| The most effective ways to protect yourself and others
| against COVID-19 are to frequently clean your hands, cover
| your cough with the bend of elbow or tissue and maintain a
| distance of at least 1 meter (3 feet) from people who are
| coughing or sneezing. See basic protective measures against
| the new coronavirus for more information.
|
| They don't say it useless, just they not recommend it
| watwut wrote:
| If using mask helps lower probabilities then you can sew
| your own. Which means you can wear it without buying one.
| It might not be as great as official one, but still
| probabilities.
| robocat wrote:
| > Disposable face mask can only be used once.
|
| They can be cleaned. It's not ideal, but very likely
| better than nothing. Sorry, can't find link, but they
| tried a variety of different techniques to hit on one
| that worked.
| leggomylibro wrote:
| So, how does the PCR-based testing work? Is it just the usual
| gene amplification steps?
|
| * Get DNA out of cells and unwrapped from their histones.
|
| * Cleave the DNA sample with restriction enzymes at boundary
| sites which should mark the start/end of a stretch of viral DNA.
|
| * Amplify the sample with PCR, using primers which match
| stretches of viral DNA.
|
| * Run a gel electrophoresis and look for a mass of DNA that
| matches the expected size of the stretch of viral DNA.
|
| Is that how things work, or are these kinds of diagnostics done
| differently?
| projektfu wrote:
| Sort of. There are now reagents that can fluoresce as the
| strand is elongated allowing instantaneous reading.
|
| Also, for an RNA virus, it starts with reverse transcriptase.
|
| https://en.m.wikipedia.org/wiki/Real-time_polymerase_chain_r...
| vikramkr wrote:
| qPCR doesn't use a gel, and you get specificity by using
| primers to the viral dna (which are what tell you the part you
| start and end amplification at), not restriction enzymes, but
| yes conceptually similar sort of idea. You set up reaction
| conditions so that at the end of the run, if there was any
| viral dna at the start, there's now a lot more for you to
| detect, while if there wasn't, you just see the background
| since nothing else should have been replicated. I believe the
| reagent issue with the original run of tests from the CDC had
| to do with the controls you set up to show that nothing
| amplifies if you don't have any virus (since you can't just run
| one tube and see if there's a signal, you've got to run a few
| for reundancy and run samples where you should and should not
| see signals to make sure you are seeing signals where you
| should, and the reaction worked, so your signal from the
| patient samples are accurate)
| mbreese wrote:
| It's an RNA virus, so you start by isolating RNA and then using
| a reverse transcription reaction to make cDNA from the RNA.
| Then you use viral-specific primers in a traditional PCR. Most
| of the tests that I've seen presented have then be real-time
| qPCR tests as opposed to gels, but for the most part, you're
| not far off. Also, restriction digests aren't required.
|
| Note: I haven't seen any of the protocols, just what I've been
| able to learn from press reports.
|
| Edit: Here's a link to the CDC's panel protocol:
| https://www.fda.gov/media/134922/download
|
| And to add Wikipedia's page on real-time PCR (not to be
| confused with RT-PCR, which is also used here):
| https://en.wikipedia.org/wiki/Real-time_polymerase_chain_rea...
| . However, the crux of it is that the reaction contains a
| chemical that fluoresces in the presence of double-stranded
| DNA. As the PCR reaction progresses, if there is a valid
| template in the original mixture (i.e. if there is virus
| present), then there will be a detectable amount of DNA present
| after a number of PCR cycles. The lower the number of PCR
| cycles required to detect this fluorescence, the more viral RNA
| was present in the initial sample.
| leggomylibro wrote:
| Neat, thanks - it's amazing how quickly sequencing
| technologies have evolved.
| mbreese wrote:
| This isn't sequencing... you'd use sequencing to identify
| novel mutations or strains of the virus. This is a set of
| known PCR primers that amplify the virus's RNA. You could
| (in theory) also use a similar approach to identify
| specific strains of the virus, but this shouldn't be the
| priority at the moment.
|
| While you could have an assay that used sequencing, it
| wouldn't be nearly as fast or cost efficient.
| VectorLock wrote:
| This CDC document was an interesting read. I found this
| part particularly fascinating.
|
| >RNA isolated and purified from upper and lower
| respiratory specimens is reverse transcribed to cDNA and
| subsequently amplified in the Applied Biosystems 7500
| Fast Dx Real-Time PCR Instrument with SDS version 1.4
| software. In the process, the probe anneals to a specific
| target sequence located between the forward and reverse
| primers. During the extension phase of the PCR cycle, the
| 5' nuclease activity of Taq polymerase degrades the
| probe, causing the reporter dye to separate from the
| quencher dye, generating a fluorescent signal. With each
| cycle, additional reporter dye molecules are cleaved from
| their respective probes, increasing the fluorescence
| intensity. Fluorescence intensity is monitored at each
| PCR cycle by Applied Biosystems 7500 Fast Dx Real-Time
| PCR System with SDS version 1.4 software.
| leggomylibro wrote:
| Right, sorry...I sort of think of PCR as 'grep for
| genomes', even though it doesn't really 'read' the DNA.
| kylebenzle wrote:
| You mean in the last 20 years? Yeh, it was super fast.
| pbhjpbhj wrote:
| As someone outside the industry it _appears_ [emphasis
| there] to have gone from "we can take a few weeks and
| test you for a specific disease susceptibility" to "place
| your finger here and then grab a coffee ... sorry for the
| wait, OK we have details on 100 different diseases now"
| in a matter of 2 or 3 years.
| leggomylibro wrote:
| Yes, that is what I mean.
|
| I can't tell if you're being sarcastic or not, but 20
| years is a very short amount of time if you look back on
| the history of the advancement of engineering and our
| understanding of the world. It's very exciting,
| especially when you look at how little the basic
| operating concept of computers has changed in the same
| timeframe.
| Markoff wrote:
| by June when it will be available I'll be either dead or immune,
| same with most of the population
| aliljet wrote:
| These kinds of engineering/science solutions to a hard problem
| are the bread and butter of a community like this. Where can
| engineers pool their resourcing and work together to assist in
| the fight?
| sdiq wrote:
| Cheap and fast screening tests for a number of health conditions
| are commonly available. However the sensitivy and specificity of
| these tests tend to be lower than the PCR, for example. Once a
| person tests positive in the first screening test, a second
| confirmatory tests is then ordered. This test should thus be one
| such fast screening test and would certainly help in a place like
| Africa.
| yread wrote:
| Here is a list of potential diagnostic tests for COVID-19
|
| http://www.finddx.org/covid-19/
| salimmadjd wrote:
| From their website [0] my guess is their test is ELISA [1] based
| or similar method of detecting if the human body has had an
| immune reaction to the virus in the amount that is detectable.
| Where as the more expensive test is PCR based [2] that requires
| the heating-cooling cycles and machines to do it.
|
| The PCR-based test basically take the RNA of the virus converts
| it to DNA and then doubles the amount of DNA every heating cycle.
| Assuming we are talking about real-time PCR the PCR cycle of
| double is what takes time.
|
| I have not seen the data on the incubation period and the immune
| response, to know if these immune detection tests will be able to
| provide early detection for asymptomatic case . It's probably for
| symptomatic cases and wanted to ensure it's not flu or another
| infection and it's COVID-19. This is not to say the test is
| useless. It actually great inexpensive way of testing the
| population with symptoms and using more expensive and timely test
| for early detection. Reducing the overall burden.
|
| worth mentioning are other initiatives that are focusing on
| cheaper and faster PCR process (though with potential of higher
| false negative and positive results) [3]
|
| [0]https://mologic.co.uk
|
| [1]https://en.wikipedia.org/wiki/ELISA
|
| [2] https://en.wikipedia.org/wiki/Real-
| time_polymerase_chain_rea...
|
| [3] https://twitter.com/JMRothberg/status/1238115465467133959
| entee wrote:
| RT-qPCR is indeed the common detection method right now. RT
| (reverse transcriptase) converts RNA->DNA, PCR (polymerase
| chain reaction) doubles DNA by replicating it over and over in
| heat cool cycles. To a first approximation, you get 2^n copies
| of the RNA (it was converted to DNA) where n is the number of
| heat cool cycles. By adding a fluorescent tracer, you get the q
| (Quantitative), so you can see how much DNA exists at each
| cycle. You can then fit a curve and see how much RNA (via its
| DNA complement) existed in the original sample. It's not
| actually that slow, you can do this in a couple hours if you
| have the right setup. The bottleneck is you do need time for
| the heating and cooling cycles. You also need to extract RNA
| from the sample first, which could be another bottleneck. I'm
| not totally clear on the relative cost, a good ELISA would
| eventually be cheaper, but qPCR itself isn't very expensive.
| The benefit is that qPCR is extremely sensitive, you WILL see
| if there is virus in the bloodstream. You can even use swabs
| and avoid blood altogether. Also, the minute you have a viral
| genome, you can make a qPCR test, you just need the sequence.
| That said, if you cleared the infection you will be negative
| under RT-qPCR.
|
| An ELISA works differently. In this case you would present a
| part of the viral protein, the patient's antibodies will bind
| to it, and you then use another antibody (this one is
| conjugated to some sort of readout method, fluorescent or
| biochemical) which binds to _generic human antibody_. Now you
| have a stack: viral protein <> patient antibody <> readout
| antibody. You read out the signal provided by your readout,
| usually some sort of colorimetric thing (see home pregnancy
| tests, also an ELISA, slightly different configuration though).
| This works fast, can be manufactured in bulk, BUT requires do
| you have a protein(s) (in this case the viral protein) that
| is/are universally recognized by patient antibodies. It's a
| little trickier to develop. You also need to produce that
| protein at scale which can take a little time as well. Major
| benefit: with a good ELISA you WILL see not only whether
| someone IS infected but whether someone WAS infected for some
| period after illness regardless of symptoms. This is
| essentially the only way you'll get a really good number for
| baseline infection rate. That said, you likely actually need a
| blood draw.
|
| In short, we need both, we probably could do a lot better than
| we are doing with qPCR in testing volumes and we could also
| really use an ELISA.
|
| Source: PhD biochemist, have personally run these assays in
| various forms.
|
| EDIT: Acronym expansion, source
| maxerickson wrote:
| What's the approximate setup and validation time once you
| have a sequence?
|
| (that is, what's the scale of the fuck up that the machine
| testing is still being brought online)
| entee wrote:
| I used to set up and run a large plate of qPCR (we didn't
| use the RT step in our particular use case) in an hour or
| so. Mind you this was for something like 200 samples. It
| took 2-3h to run the actual machine. If I was setting up
| such an assay, I'd order a bunch of different primers (you
| need DNA to make DNA) and run a bunch of plates with as
| many samples as I could to see what primers worked best.
| You'd include a bunch of negative controls, ideally some
| controls from patients/cultures infected with similar but
| not identical virus (for example a different coronavirus).
| To develop an RT-qPCR assay would take a week or two (rough
| guess), I think it took about a week to develop the WHO
| assay.
|
| From what I can tell (mostly anecdotal and other data from
| friends I trust) the CDC assay used bad primers, they were
| noisy, showing a bunch of false positives. They also used a
| potentially dodgy fluorescence readout. I used to use the
| same readout, but our scenario was full of internal
| controls and the input sample was far more consistent. For
| human sample data a different fluorescent method that is
| more reliable should have been used.
|
| Important ways this can be screwed up: it's helpful to use
| the same machine, the same protocol every time. This is
| because qPCR is an exponential assay, which means small
| errors can have big repercussions.
|
| TLDR: Scale of fuckup here is massive. This really isn't
| that hard, and we could just have used what the WHO/others
| were using. I have no idea why they decided to go their own
| way.
|
| more info: https://www.propublica.org/article/cdc-
| coronavirus-covid-19-...
| gewa wrote:
| Maybe one should note, that there are two possible Elisa
| based strategies. Yes, You can present some viral protein to
| detect antibodies produced by the body after serum
| conversion, as you said. This serum conversion takes at least
| a week to happen and you need a blood sample. On the other
| hand you can also immobilize antibodies specific to the viral
| proteins and directly detect the virus. This is possible
| immediately after infection and fluids like sputum or saliva
| can be used. Both strategies are under development for quick
| tests right now.
| joshuamcginnis wrote:
| Five days ago, it was reported that a German biotech company
| had already produced 4 million tests.[0]
|
| "The tests use what's called the polymerase chain reaction, a
| diagnostic method recommended by the WHO that amplifies the
| virus's genetic code so it can be detected before the onset of
| symptoms. The kit comes with two vials: a primer to help detect
| an infection, and a synthetically engineered piece of the
| virus, which labs use to produce a surefire positive match to
| ensure their machines are working correctly. A lab technician
| combines these ingredients with a patient's mucus sample--
| usually from a throat or nasal swab--and results are usually
| available in a few hours."
|
| Coincidentally, I recently discovered the burgeoning biohacking
| scene in which many folks are already using affordable PCR
| thermocyclers in their home labs to do DNA amplification and
| crispr-cas experiments. I do fungal sequencing for phylogeny
| myself.
|
| Given the simplicity of the testing process using PCR, why does
| it seem like the US is moving so slowly with getting tests in
| peoples hands? Is it the primer or control virus synthesis? Is
| it the manufacturing process? Is it red tape? If so, which
| specifically? Is it poor communication? Is it a confluence of
| factors?
|
| Why isn't every local university or lab working together to at
| the least, copy the Germans protocol and get to work on
| manufacturing ASAP? Why isn't there a line of people outside
| these labs ready to drop-off their sample and get the results
| online? Where is the American version of the aforementioned
| biotech startup?
|
| This epidemic and the general response has only reinforced my
| belief in the future of citizen science and the widespread
| accessibility of indie biohacking tools and methodologies.
| There are just too many misaligned incentives in pharma
| research, leaving huge gaps in the ability to bring new tests
| and drugs to the market. Look no further than the antibiotic
| resistant drug problem.
|
| [0]https://www.msn.com/en-us/finance/companies/a-berlin-
| biotech...
| amelius wrote:
| Wouldn't a far less specific test do the trick as well?
|
| If we had a cheap test that tells us whether we have some kind of
| illness, corona-flu included, then I'd say that would be
| tremendously useful.
| afterburner wrote:
| How many can they make?
| bolasanibk wrote:
| From the article: Mologic and the Institut Pasteur have joint
| capacity to produce 8 million tests a year
| blueyes wrote:
| I'd just like to note that, while we should be conducting many
| more tests, we should also be aware of the danger of false
| positives, and the burden that places on individuals and systems.
| Some of these tests are just not very accurate, according to an
| MD I know.
| aldoushuxley001 wrote:
| Still better to have as one of many screening options
| lukifer wrote:
| Always a concern, but under the present circumstances, a false
| positive (someone quarantines for two weeks who doesn't need
| it) is far better than a false negative (someone has false
| confidence in attending public places).
|
| Unlike other false positives that could lead to
| unneeded/harmful interventions (surgery, chemo), erring on the
| side of false positives would actually be desirable for
| COVID-19.
| jschwartzi wrote:
| I'd rather not be quarantined with a bunch of sick people for
| two weeks if I'm not actually sick. The risk of me getting
| the virus is much higher there than among the general
| populace. So I disagree that there are no downsides or risks
| for a false positive here. Especially as the disease has a
| chance to kill me.
| jedberg wrote:
| You quarantine at home.
| xnyan wrote:
| All the restaurants and bars of California and New York
| are closing or are closed and all the people that work
| there are hourly wage. How how long do you think they
| will still have homes? Not trying to be alarmist but I
| also don't see how people making an hourly wage are going
| to continue living in their very expensive states without
| income.
| sp332 wrote:
| Most NYC landlords have agreed to a 90-day hold on all
| evictions. So... about 90 days I guess.
| jedberg wrote:
| Unless the government backstops it, they won't. It is and
| will be a huge problem.
|
| Some states are banning evictions for a few months, so at
| least there is that option. But it just means they'll be
| homeless in June instead of April.
| jacurtis wrote:
| Self-quarantine means they send you home and tell you not
| to leave for 2 weeks.
|
| Unless you are in such an extreme case that you need a
| respirator or something, in which case they will
| hospitalize you and you might be around other diseased
| victims, but if you are in that condition then it is
| probably not a false positive. There is a shortage of
| hospital beds worldwide right now, so they are sending
| everyone home unless hospitalization is considered life-
| saving.
| fma wrote:
| You may have misheard the MD. The current tests have a very low
| false positive rate. That means if the test says you have
| Coronavirus, you have it. There's no "burden".
|
| Where the tests are "not very accurate" is the false negative.
| The false negative rate can be as high as 50-60%, depending on
| tests and how it's administered. Sometimes they will conduct
| the test twice to improve accuracy.
|
| The Roche ones recently approved have a lower negative test
| rate (10%?)
|
| Edit: I removed my mention of 0% false positive rate because
| nothing in life is absolute.
| whatshisface wrote:
| A 0% false positive rate is not possible. What if they switch
| your sample with someone else's while it's being handled by a
| human?
|
| Edit:
|
| > _That means if the test says you have Coronavirus, you have
| it._
|
| This line implies the parent comment is talking about the
| false positive rate of the entire testing process that
| results in you being told you're infected, not PCR as a
| platonic ideal, theoretical process.
| joking wrote:
| That's a protocol fault and has nothing to do with the
| accuracy of the test
| fma wrote:
| From the FDA itself. Note how firm they are in regards to a
| positive, vs how cautious they are in regards to a
| negative. If you have COVID-19 RNA in your body...you have
| the virus.
|
| What does it mean if the specimen tests positive for the
| virus that causes COVID-19? A positive test result for
| COVID-19 indicates that RNA from SARS-CoV-2 was detected,
| and the patient is infected with the virus and presumed to
| be contagious
|
| What does it mean if the specimen tests negative for the
| virus that causes COVID-19? A negative test result for this
| test means that SARSCoV-2 RNA was not present in the
| specimen above the limit of detection. However, a negative
| result does not rule out COVID-19 and should not be used as
| the sole basis for treatment or patient management
| decisions. A negative result does not exclude the
| possibility of COVID-19.
|
| https://www.fda.gov/media/135662/download
| [deleted]
| rectang wrote:
| > _A positive test result for COVID-19 indicates that RNA
| from SARS-CoV-2 was detected, and the patient is infected
| with the virus_
|
| You still haven't addressed the possibility of a protocol
| error such as a switched sample. The lab test itself may
| never produce false positives, but that emphatically does
| not mean that if the lab test comes back positive there
| is a 100% guarantee that the patient is infected.
| fma wrote:
| Considering the context that I replied to is "we should
| also be aware of the danger of false positives", I think
| given the FDA source I posted (and what I've read
| elsewhere) I can say that there is absolutely no need to
| be aware of a danger of false positives in terms of
| disrupting people's lives.
|
| If you want to argue on the fact of life that nothing in
| life is absolute. Fine. you win. If administered
| properly, and the test kit detects a presence of
| COHVID-19 RNA in your body, and the person telling you
| the results is not drunk, then the results is as close as
| 0% as practical.
| irishsultan wrote:
| That's still not a false positive rate of the test.
|
| But I agree that 0% false positive rates are going to be
| nearly impossible to achieve (for just about anything that
| isn't mathematics).
| [deleted]
| kylebenzle wrote:
| Don't you know you get downvoted here on HN for telling the
| truth.
|
| These idiots like to think they've got it all figured out.
| Of course there is no such thing as a 0% false positive
| test.
| timhigins wrote:
| "Clinical characteristics of 24 asymptomatic infections with
| COVID-19 screened among close contacts in Nanjing, China." -
| https://link.springer.com/content/pdf/10.1007/s11427-020-166.
| ...
|
| It seems asymptomatic patients can test negative _multiple
| times_ on RT-PCR assays but be diagnosed other ways.
|
| I've read somewhere that at least in China, the specificity
| of the PCR tests is only 60-70%, leaving ~30% undetected.
|
| From the Discussion section of this paper:
| https://pubs.rsna.org/doi/10.1148/radiol.2020200642:
|
| "According to current diagnostic criterion, viral nucleic
| acid test by RT-PCR assay plays a vital role in determining
| hospitalization and isolation for individual patients.
| However, its lack of sensitivity, insufficient stability, and
| relatively long processing time were detrimental to the
| control of the disease epidemic. In our study, the positive
| rate of RT-PCR assay for throat swab samples was 59% (95%CI,
| 56%-62%) which was consistent with previous report (30 - 60%)
| (6). In addition, a number of any external factors may affect
| RT-PCR testing results including sampling operations,
| specimens source (upper or lower respiratory tract), sampling
| timing (different period of the disease development) (6), and
| performance of detection kits. As such, the results of RT-PCR
| tests must be cautiously interpreted."
| andrewla wrote:
| > The current tests have a 0% false positive rate.
|
| Need a citation on this. In order to even make a strong
| statement about the false positive rate you need to have some
| sort of alternate confirmation mechanism, usually clinical
| diagnosis or another more comprehensive test. That kind of
| work takes time and we haven't gotten to the point where we
| know this.
|
| False positives in the test are one possible reason for the
| resurgence in Singapore; the initial screenings were
| overreporting the number of cases leading to a false sense of
| security, followed by a surge in real cases as the spread
| continued.
|
| EDIT: A quick look at some of the tests available indicate
| that currently providers are not publishing
| specificity/sensitivity numbers in general under the
| accelerated release guidelines. One I did find was
| biomedomics test [1], which claims "The overall testing
| sensitivity was 88.66% and specificity was 90.63%", so ~10%
| of negative cases will show as positive.
|
| [1] https://www.biomedomics.com/products/infectious-
| disease/covi...
| makomk wrote:
| That's an antibody-based test not approved for diagnostic
| use in the US, which is faster but less accurate than the
| RT-PCR ones currently being used.
| andrewla wrote:
| It's just the only one that I could get numbers on. So...
| show me sensitivity/specificity numbers that show a 0%
| false positive rate. The CDC PCR test [1], for example,
| has some data and no false positives, but the sample
| sizes are so small (107 known negatives tested) that the
| best we can estimate is ~96% specificity.
|
| [1] https://www.fda.gov/media/134922/download
| DennisP wrote:
| This sounds like something we could really use in the U.S., too.
| baybal2 wrote:
| And not a single detail on what they are...
|
| Antibody tests are more suitable for test strips, and work under
| 30m, but they need blood test.
|
| Few companies in China are already marketing 30 minute PCR
| systems. One from Xiamen, another from Nansha.
| mbreese wrote:
| > Using technology from home pregnancy and malaria tests, its
| saliva and finger-prick kit could be ready for sale by June for
| less than $1 apiece.
|
| Based on this, I'd guess they are talking about an antibody
| based test. There are point of care Influenza tests that work
| on the same principle. Probably not as sensitive as a PCR test,
| but definitely cheaper and faster -- if you can get a good
| antibody.
| projektfu wrote:
| A direct antigen test can work if enough virus is shed. For
| example, there is a coronavirus fecal antigen test for dogs.
| The technique is ELISA, like for antibody tests.
| kylebenzle wrote:
| Agree, tried to figure out how they got an rt-pcr machine that
| small, then realized the whole article is bullshit. I guess we
| are in for a lot of this nonsense.
| mmmrtl wrote:
| It's real tech - miniaturization with microfluidics allows
| shorter cycles -> faster results. But it's not clear whether
| any of these companies are yet making enough machines to
| help, or if it's just PR. Probably the latter.
|
| https://www.chinadailyhk.com/article/121312
| montalbano wrote:
| For another novel detection method which may be suitable for low-
| cost implementation see this post
| https://news.ycombinator.com/item?id=22592173
| mehrdadn wrote:
| What's the current best false negative rate of any coronavirus
| test?
| rhizome wrote:
| A test for $1 can be a test for free.
| apk-d wrote:
| A test for $1 can be afforded by anyone.
| pbhjpbhj wrote:
| I'd say "can be afforded by the World for everyone". Sure,
| the average GNI (gross nat. income) for the poorest countries
| is about $2 (USD) per day, but affordability is more complex.
| However, if we taxed the World, and paid according to ability
| of nations to pay ... I mean USA could probably pay it for
| everyone and only have to not build an aircraft carrier
| (https://en.wikipedia.org/wiki/Gerald_R._Ford-
| class_aircraft_... says that is $12B, money to spare!).
|
| [Yes, finance isn't that easy, the knock on effects would
| make the cost possibly greater, maybe less(!)?]
| apk-d wrote:
| The logistics of getting goods such as food and medicine
| into third world countries have hardly anything to do with
| their manufacturing price. Even once you get them there,
| distribution is a nightmare. Obviously I'm not referring to
| countries with no actual economy to speak of.
| nlh wrote:
| Someone sent me this link recently. Can anyone provide some color
| on what's actually being sold here? Is this just fraud or are
| there cheap tests already available in China?
|
| https://www.alibaba.com/trade/search?fsb=y&IndexArea=product...
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