13 ms·

What other coronaviruses tell us about SARS-CoV-2

205 points by theafh 7y ago

nfc 7y ago
"This deletion likely hindered its ability to bind effectively, making it harder to produce severe infections. Such evolution by deletion is actually a common feature of these viruses." Is this really the case?, how would that be a common feature?, how are the strains where this deletion takes place more successful than those where it doesn't happen?, is it because it favors faster spread and somehow the organisms infected by these strains with deletion become inmune also to strains without deletion?, or there are other mechanisms that come into play?
- vikramkr 7y ago
  Deletion is an easy mutation to occur in the process of replicating a genome. The reason these strains would be successful is because they dont kill or hurt their hosts that badly. If the infected person is bedridden, they're not going to be out and about spreading the virus, while a less severe infection would make it easier for them to mingle amd infect others to pass on the gene pool.
  - nfc 7y ago
    So from what you are saying the explanation for the paragraph from the article would be that a more severe infection would be more likely to have R0 < 1, so on aggregate viruses would "commonly" evolve this way. I understand this, but thank you for the reminder of the mechanism :) However if the the R_0 of COVID-19 is between 1.4 and 5 (https://en.wikipedia.org/wiki/Basic_reproduction_number https://en.wikipedia.org/wiki/Basic_reproduction_number), how likely would it be that another mutation more lethal would appear and still be successful?, that is with R_0 > 1. I think that's a more relevant question than whether most successful mutations will be less lethal. Specially knowing that one of the characteristics of the virus is asymptomatic spread which could invalidate the point of a more lethal strain having much lower R_0.
    - vikramkr 7y ago
      I've linked at the bottom a great video from minute earth with some food for thought on this that I recommend watching, I found it really helpful/interesting. R0 is not necessarily inherent to the virus (although I think australia might use a more restrictive definition that makes it more inherint to the virus), it's based on our behavior to a large extent. MinuteEarth has a great video (i'll link it below) that discusses how Cholera, for example, stayed very severe and yet had a high R0 because it spread through sewage and the sanitation system was not so great, so it didn't matter whether people stayed home since their fecal matter ended up in drinking water anyway. But after sanitation systems improved, cholera's R0 dropped and the less severe mutation meaning higher r0 thing kicked in since you needed more human interaction to get it to spread again. So with coronavirus, if it mutates to become more severe, maybe it'll mutate back to a SARS like form where it's super lethal which also means it doesn't spread really far. Both SARS and ebola are on that end of the spectrum. But let's say people get overconfident and think they've beat it and don't stay home in the earlier days of the infection when they're not bedridden yet, you could still get a lot of spread. Or, let's say it becomes more severe, but also gains the ability to survive on surfaces for weeks and become airborne when dislodged. Now, your santation procedure for your instacart delivery is no longer enough and the virus could keep spreading through a lockdown. And then there are diseases like HIV, which are ultimately incredibly severe, but have a latency period that allows for infection to keep occuring even with a mechanism of transmission that is a lot more effortful than accidentally coughing near someone. As you mentioned, the asymptomatic spread aspect has echos of htis, where even though the mutation could be severe, it might not have the chilling effect on transmission you'd expect because of asymptomatic and presymptomatic spreaders. So long story short, I don't know how likely it is that a more lethal mutation appears, but I do think you're right in intuiting that it is possible. Perhaps there are ways to estimate a probability by running simulations on the genome of the most common types of mutations to see what sort of effects we can anticipate. SARS-COV-2 is very closely related to SARS-COV after all, it's just a slightly different straing, even though the SARS outbreak and the COVID outbreaks look so different. I don't think it's impossible that COVID could mutate to have SARS' severity while maintaining COVID's presymptomatic shedding and asymptomatic spread. Maybe as we learn more about it we'll discover that both come from the same mutation and it's a fundamental tradeoff, but I think it's possible that that's not the case. A disease's guide to world domination from minuteearth: https://www.youtube.com/watch?v=Ch4d9qEKmHE https://www.youtube.com/watch?v=Ch4d9qEKmHE
- Symmetry 7y ago
  Scientists speculate that while this change slows down reproduction and decreases virulence it also makes it harder for the immune system to track down virus infected cells, so it basically slows down the infection. In the long run zoonotic viruses tend to become less deadly. But I wouldn't expect this sort of mutation to be selected for when the number of cases is increasing exponentially.
dmix 7y ago
> In cats, for example, infection with feline enteric coronavirus may last for months or longer. When this happens, the virus mutates so much that its very nature seems to change. What starts out as a relatively mild gastrointestinal infection eventually causes serious peritonitis (inflammation of the membrane lining the abdominal wall) in some animals. Examining the virus at this point in the infection, researchers found that the mutations had resulted in the emergence of a related virus, feline infectious peritonitis virus — and this one has a higher fatality rate. Can someone explain this to me, are they saying that the virus mutated into another virus? What conditions would it need to be a new virus rather than a variation of the original one?
- deleted 7y ago
  [deleted]
- celticninja 7y ago
  this also sounds a bit like the new childhood illness that health services are being warned about.
  - sjg007 7y ago
    Could be. Also a good reason to keep the schools closed.
    - celticninja 7y ago
      I agree. I certainly won't be sending mine back in a rush, not until I am confident they have a manner of control rather than just "well the health services won't be overwhelmed by the dying"
- maxerickson 7y ago
  Seems to be arbitrary: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-infectious-peritonitis https://www.vet.cornell.edu/departments-centers-and-institut...
- deleted 7y ago
csours 7y ago
> "Could SARS-CoV-2 become endemic among humans and just never go away? What then?" I really don't see how we can avoid this. I think it will take too long to create a vaccine, and there will be mutations and recombinations that reduce vaccine effectiveness. I'd love to be wrong though.
- standardUser 7y ago
  "I really don't see how we can avoid this." Some viruses just peter out, but I don't assume this one will just because it's possible. Some virus become endemic, but why would we assume that about this virus either?
  - SpicyLemonZest 7y ago
    There are a handful of endemic coronaviruses, and historical respiratory disease pandemics have consistently become endemic, so it seems like a reasonable assumption.
- SketchySeaBeast 7y ago
  Just like the normal flu and H1N1 I imagine it may just become part of the yearly flu-shot - I imagine giving a large proportion of the population resistance changes the math considerably on how much it affects us.
  - kzrdude 7y ago
    Who gets a yearly flu shot? Genuinely curious.
    - baddox 7y ago
      I'm sure it depends a lot on your location and peer group. In San Francisco, where I live, it's very common for healthy 20- and 30-somethings to get the flu shot every year. I try to remember to get it every year, and there's always friends or coworkers reminding everyone about it every year.
    - 7y ago
jjuel 7y ago
This is what worries me the most. More research needs to be done, but if you can get reinfected it seems like herd immunity is a pipe dream. If immunity doesn't last long then does a vaccine even work? Now I am very clueless on all this so I could be way off. In fact if someone does know more about virology and could explain to me where I am wrong that would be great!
- f38zf5vdt 7y ago
  Immunity will presumably last at least a few months, and the problem always reaches its greatest severity in the winter months because people are indoors more. We will just default to the influenza model, where there are circulating betacoronaviruses every season and we try to predict and vaccinate against them. The Middle East deals on and off with MERS.
  - matwood 7y ago
    Presumably immunity goes away once the antibodies are gone, but does the body remember the virus for next time? Assuming the virus does not mutate too much from year to year, at what point will it not be novel anymore to the human body? Will subsequent infections be easier for the body to fight?
    - christkv 7y ago
      From what I understand you build some resistance as you are exposed to multiple variants of the same flu virus so it's quite possible this would hold for coronavirus making refection less likely to lead to a severe infection. Lets also not forget that there is likely to be well studied effective anti-virals at some point like we have for the flu today.
- kbenson 7y ago
  If you get reinfected, can you expect the same level of severity? That's what I'm wondering. Does having antibodies for a a virus that's very close, but not quite exact result in less severe symptoms and/or a quicker time to showing symptoms? If so, that doesn't necessarily help the spread greatly right now, but it does point towards a time in the future where this virus actually is more like the regular colds and flus we are used to.
dathinab 7y ago
Can you really infer much from other corona viri? I mean "corona virus" is a extreme corse category of viri which contains all viri of which the outer shell has a certain kind of structure which looks like a corona (crown). While this puts some constraints on how the virtual can survive outside if the body and similar thinks it still does say hardly anything about e.g. what cells the virus hijacts, what syntoms it causes, etc. Edit: maybe from other SARS corona viri
- jnbiche 7y ago
  The plural is virus is viruses, or "virus" if you insist on its Latin form. It's a Latin word, but it only occurs in Latin as a singular collective noun: https://jdebp.eu/FGA/plural-of-virus.html https://jdebp.eu/FGA/plural-of-virus.html
  - anticsapp 7y ago
    True, but everyone used "virii" on downloadable sections of hacker BBSes from the 80s/90s. It's a hard habit to break.
    - droopyEyelids 7y ago
      And if you don't break it, then eventually Websters will add it to the dictionary and you'll have been right the whole time.
- gus_massa 7y ago
  The classification of virus is difficult, but it is not based only in the shape. The shape may give some hints, and help to get a friendly name, but it is not the only property. Moreover, in the last (10?) years it is easier and easier to sequence the genome of them, and understand the relations. For an more familiar example, think about the distinction of rabbits and hares. I can't for the life of me distinguish them, but they are not very related and biologist can classify them and get the more related species of them (specially if the rabbit/hare is dead and they can open it and look at the inner parts and bones, or even better, make a genetic analysis). Another example is sharks vs dolphins. Both live in water and they look somewhat similar. (I think I can distinguish them.) Why are sharks a type of fish, but dolphins are not?
29athrowaway 7y ago
There are many more coronaviruses in the wild and we will continue to see pandemics until unsanitary practices like wet markets with exotic animal products are outlawed. Simian Inmunodeficiency Virus (SIV) could jump to humans, becoming HIV, through the manipulation of raw meat from infected apes. We have immunity or at least some control over diseases coming from more common species of cattle.
- the_af 7y ago
  > we will continue to see pandemics until unsanitary practices like wet markets with exotic animal products are outlawed I'm really no expert and don't know what to think, but Wikipedia asserts that as of April 2020 investigations are still trying to determine whether the Huanan market was really the source of COVID19. Even if it was, can we even conclude getting rid of these markets would solve pandemics as a general problem? So at this point we can't really say the "fix" is to remove these markets, can we?
  - 29athrowaway 7y ago
    It is known it comes from certain animals, like bats. So, how can the virus jump from a bat to a human, either directly or indirectly? Sure, you can randomly run into a bat anywhere in the world. I know a person that found a bat in her balcony some weeks ago. But the probability that the virus jumps across species is low. You have to increase the odds, and a good way of doing that is creating a wet market full of them. And it has been known for a long time that those markets were a disaster waiting to happen.
    - deleted 7y ago
      [deleted]
    - the_af 7y ago
      Maybe it happened like that, maybe it didn't. The Wikipedia page on the (possibly) zoonotic origins of SARS-CoV-2 mentions lots of questions and uncertainties, including whether the Huanan wet market was the source at all (because of the raw meat) or simply a place where infected people spread it: https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2#Reservoir_and_zoonotic_origin https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr... I'm not going to quote every paragraph casting doubt, but take a look at this (from Wikipedia): > The first known infections from the SARS-CoV-2 strain were discovered in Wuhan, China.[12] The original source of viral transmission to humans remains unclear, as does whether the strain became pathogenic before or after the spillover event.[18][57][15] Because many of the first individuals found to be infected by the virus were workers at the Huanan Seafood Market,[58][59] it has been suggested that the strain might have originated from the market.[15][60] However, other research indicates that visitors may have introduced the virus to the market, which then facilitated rapid expansion of the infections. Note that "facilitating rapid expansion" may simply mean that because it was a place with a lot of people grouped together, the infection could have spread more easily -- the reason we need social distancing now -- but it doesn't automatically mean it has to do with raw meat of exotic animals. Now, it can be the problem is raw meat after all! But it seems to me research is still ongoing about whether this was the real culprit. That's all I'm saying.
otfc321 7y ago
Supporting the the continued lockdown is not only unamerican and illegal but it is also RACIST. All the H1-Bs in California are going to be screwed within another month. Hope you like being racists you liberals!
clarkevans 7y ago
> Does the amount of virus exposure affect disease severity? It looks that way. Besides reducing the transmission rate, social distancing measures could also be reducing the initial viral load of each exposure, leading to milder disease profiles, lowering population hospitalization and fatality rates.
eveningcoffee 7y ago
Some people have tried to infer SARS-CoV-2 severity based on common corona viruses https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102597 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102597 (currently hospitalized 89998, CFR so far in hospitals 17%). But, it does not mean that the question is wrong of course and it is an interesting piece. Also Sweden is not having some clever strategy. Anders Tegnell messed up so bad that they had to claim it to be a strategy https://www.project-syndicate.org/commentary/swedish-coronavirus-no-lockdown-model-proves-lethal-by-hans-bergstrom-2020-04 https://www.project-syndicate.org/commentary/swedish-coronav...
- toolz 7y ago
  Why does it seem like both sides seem to be so sensationalist about Sweden. They have middle of the road all-cause mortality and most recently their sero studies suggest an extremely low IFR but that got pulled due to bad randomization of test subjects so that might go up to middle of the road for Europe for Sweden too. They haven't performed great and not poorly either. It's strange to see people so polarized over them.
  - tigershark 7y ago
    Because they should be compared with the neighbouring Nordic countries. Norway 38 deaths/M Finland 37 deaths/M Denmark 76 deaths/M Sweden 244 deaths/M It’s an order of magnitude more deaths per million than Norway or Finland.
    - adamiscool8 7y ago
      But isn't that the point? They accepted more deaths up front, but over the long-run those countries should average out about the same per capita, while Sweden avoided immediate negative social/economic impacts.
      - twic 7y ago
        Perhaps. Hopefully! It's too early to know the final counts, though, which is why there is still scope for controversy.
hristov 7y ago
I think everybody should carefully read the short section that says "Does the amount of exposure affect the severity?". Some people are looking at antibody studies that show that large parts of the population are somehow affected and then doing back of the napkin math and deciding that this is really not worse than the flu in terms of death rate. They are further encouraged by the fact that people that die tend to be older and with pre-existing conditions. Then they say we should open everything up and get everything "back to normal", and sometimes they add that this is just a way to winnow out the old and the weak. As problematic as the latter statement is, the above thinking is actually dangerously optimistic. Experience shows us that in specific situations with prolonged/repeated exposure, the death rates are much higher. Also young and healthy people may get seriously sick and die due to high level of exposure. This has already been happening in hospitals that did not have sufficient protective equipment/procedures. If we open everything up and get into a situation where the virus is all over the place we can get into a horrible spiral of increased exposure and increased death rates etc.
- Bnshsysjab 7y ago
  As someone who hasn’t followed, and I understand I’m asking a random internet user this and not a scientist, but what is the definition of ‘prolonged exposure?’ Are people who contract the disease less likely to die that someone who is in close contact for a prolonged period of time? How long is that period? 15 minutes? Two hours?
  - bdamm 7y ago
    To wit; if my wife gets sick and I care for her, does that mean I am experiencing "prolonged exposure"?
    - tomrod 7y ago
      Yes.
    - code_duck 7y ago
      Being around a positive person continually for several days at home would mean a lot more exposure than many people would get when encountering others in public.
softwarejosh 7y ago
maybe all the permenant lung damage will pave way for stem cell researchers and well finally get something done
- mattkrause 7y ago
  If you’re not a biologist, it may have flown under the radar that there’s quite a bit of stem cell work going on already. The development of induced pluripotent stem cells (iPSCs), which can be made from adult tissue rather than embryos, sorta sidestepped much of the ethical debate. They’re not exactly equivalent, but iPSCs have opened the door to a lot of exciting research because you can culture tissue that’s very similar to a patient’s. A few clinical trials were starting to get underway too....
known 7y ago
Q: How close we are to achieving herd immunity? A: To achieve herd immunity we need 60-70% of the population to carry antibodies to the virus. The results of antibody tests suggest that in Europe and the US, in general, we are in the low single digits https://archive.vn/UEgL5 https://archive.vn/UEgL5
- agildehaus 7y ago
  Herd immunity threshold is (R0−1)/R0. CDC pegs R0 at 5.7 with a CI of 95%. (5.7-1)/5.7 = 82% https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article?deliveryName=USCDC_333-DM25287 https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article?deliv...
  - saalweachter 7y ago
    Oof, that's an increase over previous estimates of R0.
dr_ 7y ago
It should be noted, with respect to acquiring immunity, that with SARS-CoV(1), the amount of time after which immunity theoretically could be lost would be => 3 years. If SARS-COV-2 offers a similar level of immunity, that may not be a ton of time, but its not insignificant either, especially if a vaccine could be developed within that time frame.
Navedkhann 7y ago
The theory of using Famotidine for COVID-19 has been thoroughly explained in the following articles: https://preprints.jmir.org/preprint/19199 https://preprints.jmir.org/preprint/19199 https://preprints.jmir.org/preprint/19583 https://preprints.jmir.org/preprint/19583?

205 points by theafh 7y ago

nfc 7y ago

"This deletion likely hindered its ability to bind effectively, making it harder to produce severe infections. Such evolution by deletion is actually a common feature of these viruses." Is this really the case?, how would that be a common feature?, how are the strains where this deletion takes place more successful than those where it doesn't happen?, is it because it favors faster spread and somehow the organisms infected by these strains with deletion become inmune also to strains without deletion?, or there are other mechanisms that come into play?

vikramkr 7y ago
Deletion is an easy mutation to occur in the process of replicating a genome. The reason these strains would be successful is because they dont kill or hurt their hosts that badly. If the infected person is bedridden, they're not going to be out and about spreading the virus, while a less severe infection would make it easier for them to mingle amd infect others to pass on the gene pool.
- nfc 7y ago
  So from what you are saying the explanation for the paragraph from the article would be that a more severe infection would be more likely to have R0 < 1, so on aggregate viruses would "commonly" evolve this way. I understand this, but thank you for the reminder of the mechanism :) However if the the R_0 of COVID-19 is between 1.4 and 5 (https://en.wikipedia.org/wiki/Basic_reproduction_number https://en.wikipedia.org/wiki/Basic_reproduction_number), how likely would it be that another mutation more lethal would appear and still be successful?, that is with R_0 > 1. I think that's a more relevant question than whether most successful mutations will be less lethal. Specially knowing that one of the characteristics of the virus is asymptomatic spread which could invalidate the point of a more lethal strain having much lower R_0.
  - vikramkr 7y ago
    I've linked at the bottom a great video from minute earth with some food for thought on this that I recommend watching, I found it really helpful/interesting. R0 is not necessarily inherent to the virus (although I think australia might use a more restrictive definition that makes it more inherint to the virus), it's based on our behavior to a large extent. MinuteEarth has a great video (i'll link it below) that discusses how Cholera, for example, stayed very severe and yet had a high R0 because it spread through sewage and the sanitation system was not so great, so it didn't matter whether people stayed home since their fecal matter ended up in drinking water anyway. But after sanitation systems improved, cholera's R0 dropped and the less severe mutation meaning higher r0 thing kicked in since you needed more human interaction to get it to spread again. So with coronavirus, if it mutates to become more severe, maybe it'll mutate back to a SARS like form where it's super lethal which also means it doesn't spread really far. Both SARS and ebola are on that end of the spectrum. But let's say people get overconfident and think they've beat it and don't stay home in the earlier days of the infection when they're not bedridden yet, you could still get a lot of spread. Or, let's say it becomes more severe, but also gains the ability to survive on surfaces for weeks and become airborne when dislodged. Now, your santation procedure for your instacart delivery is no longer enough and the virus could keep spreading through a lockdown. And then there are diseases like HIV, which are ultimately incredibly severe, but have a latency period that allows for infection to keep occuring even with a mechanism of transmission that is a lot more effortful than accidentally coughing near someone. As you mentioned, the asymptomatic spread aspect has echos of htis, where even though the mutation could be severe, it might not have the chilling effect on transmission you'd expect because of asymptomatic and presymptomatic spreaders. So long story short, I don't know how likely it is that a more lethal mutation appears, but I do think you're right in intuiting that it is possible. Perhaps there are ways to estimate a probability by running simulations on the genome of the most common types of mutations to see what sort of effects we can anticipate. SARS-COV-2 is very closely related to SARS-COV after all, it's just a slightly different straing, even though the SARS outbreak and the COVID outbreaks look so different. I don't think it's impossible that COVID could mutate to have SARS' severity while maintaining COVID's presymptomatic shedding and asymptomatic spread. Maybe as we learn more about it we'll discover that both come from the same mutation and it's a fundamental tradeoff, but I think it's possible that that's not the case. A disease's guide to world domination from minuteearth: https://www.youtube.com/watch?v=Ch4d9qEKmHE https://www.youtube.com/watch?v=Ch4d9qEKmHE
Symmetry 7y ago
Scientists speculate that while this change slows down reproduction and decreases virulence it also makes it harder for the immune system to track down virus infected cells, so it basically slows down the infection. In the long run zoonotic viruses tend to become less deadly. But I wouldn't expect this sort of mutation to be selected for when the number of cases is increasing exponentially.

dmix 7y ago

> In cats, for example, infection with feline enteric coronavirus may last for months or longer. When this happens, the virus mutates so much that its very nature seems to change. What starts out as a relatively mild gastrointestinal infection eventually causes serious peritonitis (inflammation of the membrane lining the abdominal wall) in some animals. Examining the virus at this point in the infection, researchers found that the mutations had resulted in the emergence of a related virus, feline infectious peritonitis virus — and this one has a higher fatality rate. Can someone explain this to me, are they saying that the virus mutated into another virus? What conditions would it need to be a new virus rather than a variation of the original one?

deleted 7y ago
[deleted]
celticninja 7y ago
this also sounds a bit like the new childhood illness that health services are being warned about.
- sjg007 7y ago
  Could be. Also a good reason to keep the schools closed.
  - celticninja 7y ago
    I agree. I certainly won't be sending mine back in a rush, not until I am confident they have a manner of control rather than just "well the health services won't be overwhelmed by the dying"
maxerickson 7y ago
Seems to be arbitrary: https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-infectious-peritonitis https://www.vet.cornell.edu/departments-centers-and-institut...
deleted 7y ago

csours 7y ago

> "Could SARS-CoV-2 become endemic among humans and just never go away? What then?" I really don't see how we can avoid this. I think it will take too long to create a vaccine, and there will be mutations and recombinations that reduce vaccine effectiveness. I'd love to be wrong though.

standardUser 7y ago
"I really don't see how we can avoid this." Some viruses just peter out, but I don't assume this one will just because it's possible. Some virus become endemic, but why would we assume that about this virus either?
- SpicyLemonZest 7y ago
  There are a handful of endemic coronaviruses, and historical respiratory disease pandemics have consistently become endemic, so it seems like a reasonable assumption.
SketchySeaBeast 7y ago
Just like the normal flu and H1N1 I imagine it may just become part of the yearly flu-shot - I imagine giving a large proportion of the population resistance changes the math considerably on how much it affects us.
- kzrdude 7y ago
  Who gets a yearly flu shot? Genuinely curious.
  - baddox 7y ago
    I'm sure it depends a lot on your location and peer group. In San Francisco, where I live, it's very common for healthy 20- and 30-somethings to get the flu shot every year. I try to remember to get it every year, and there's always friends or coworkers reminding everyone about it every year.
  - 7y ago

jjuel 7y ago

This is what worries me the most. More research needs to be done, but if you can get reinfected it seems like herd immunity is a pipe dream. If immunity doesn't last long then does a vaccine even work? Now I am very clueless on all this so I could be way off. In fact if someone does know more about virology and could explain to me where I am wrong that would be great!

f38zf5vdt 7y ago
Immunity will presumably last at least a few months, and the problem always reaches its greatest severity in the winter months because people are indoors more. We will just default to the influenza model, where there are circulating betacoronaviruses every season and we try to predict and vaccinate against them. The Middle East deals on and off with MERS.
- matwood 7y ago
  Presumably immunity goes away once the antibodies are gone, but does the body remember the virus for next time? Assuming the virus does not mutate too much from year to year, at what point will it not be novel anymore to the human body? Will subsequent infections be easier for the body to fight?
  - christkv 7y ago
    From what I understand you build some resistance as you are exposed to multiple variants of the same flu virus so it's quite possible this would hold for coronavirus making refection less likely to lead to a severe infection. Lets also not forget that there is likely to be well studied effective anti-virals at some point like we have for the flu today.
kbenson 7y ago
If you get reinfected, can you expect the same level of severity? That's what I'm wondering. Does having antibodies for a a virus that's very close, but not quite exact result in less severe symptoms and/or a quicker time to showing symptoms? If so, that doesn't necessarily help the spread greatly right now, but it does point towards a time in the future where this virus actually is more like the regular colds and flus we are used to.

dathinab 7y ago

Can you really infer much from other corona viri? I mean "corona virus" is a extreme corse category of viri which contains all viri of which the outer shell has a certain kind of structure which looks like a corona (crown). While this puts some constraints on how the virtual can survive outside if the body and similar thinks it still does say hardly anything about e.g. what cells the virus hijacts, what syntoms it causes, etc. Edit: maybe from other SARS corona viri

jnbiche 7y ago
The plural is virus is viruses, or "virus" if you insist on its Latin form. It's a Latin word, but it only occurs in Latin as a singular collective noun: https://jdebp.eu/FGA/plural-of-virus.html https://jdebp.eu/FGA/plural-of-virus.html
- anticsapp 7y ago
  True, but everyone used "virii" on downloadable sections of hacker BBSes from the 80s/90s. It's a hard habit to break.
  - droopyEyelids 7y ago
    And if you don't break it, then eventually Websters will add it to the dictionary and you'll have been right the whole time.
gus_massa 7y ago
The classification of virus is difficult, but it is not based only in the shape. The shape may give some hints, and help to get a friendly name, but it is not the only property. Moreover, in the last (10?) years it is easier and easier to sequence the genome of them, and understand the relations. For an more familiar example, think about the distinction of rabbits and hares. I can't for the life of me distinguish them, but they are not very related and biologist can classify them and get the more related species of them (specially if the rabbit/hare is dead and they can open it and look at the inner parts and bones, or even better, make a genetic analysis). Another example is sharks vs dolphins. Both live in water and they look somewhat similar. (I think I can distinguish them.) Why are sharks a type of fish, but dolphins are not?

29athrowaway 7y ago

There are many more coronaviruses in the wild and we will continue to see pandemics until unsanitary practices like wet markets with exotic animal products are outlawed. Simian Inmunodeficiency Virus (SIV) could jump to humans, becoming HIV, through the manipulation of raw meat from infected apes. We have immunity or at least some control over diseases coming from more common species of cattle.

the_af 7y ago
> we will continue to see pandemics until unsanitary practices like wet markets with exotic animal products are outlawed I'm really no expert and don't know what to think, but Wikipedia asserts that as of April 2020 investigations are still trying to determine whether the Huanan market was really the source of COVID19. Even if it was, can we even conclude getting rid of these markets would solve pandemics as a general problem? So at this point we can't really say the "fix" is to remove these markets, can we?
- 29athrowaway 7y ago
  It is known it comes from certain animals, like bats. So, how can the virus jump from a bat to a human, either directly or indirectly? Sure, you can randomly run into a bat anywhere in the world. I know a person that found a bat in her balcony some weeks ago. But the probability that the virus jumps across species is low. You have to increase the odds, and a good way of doing that is creating a wet market full of them. And it has been known for a long time that those markets were a disaster waiting to happen.
  - deleted 7y ago
    [deleted]
  - the_af 7y ago
    Maybe it happened like that, maybe it didn't. The Wikipedia page on the (possibly) zoonotic origins of SARS-CoV-2 mentions lots of questions and uncertainties, including whether the Huanan wet market was the source at all (because of the raw meat) or simply a place where infected people spread it: https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndrome_coronavirus_2#Reservoir_and_zoonotic_origin https://en.wikipedia.org/wiki/Severe_acute_respiratory_syndr... I'm not going to quote every paragraph casting doubt, but take a look at this (from Wikipedia): > The first known infections from the SARS-CoV-2 strain were discovered in Wuhan, China.[12] The original source of viral transmission to humans remains unclear, as does whether the strain became pathogenic before or after the spillover event.[18][57][15] Because many of the first individuals found to be infected by the virus were workers at the Huanan Seafood Market,[58][59] it has been suggested that the strain might have originated from the market.[15][60] However, other research indicates that visitors may have introduced the virus to the market, which then facilitated rapid expansion of the infections. Note that "facilitating rapid expansion" may simply mean that because it was a place with a lot of people grouped together, the infection could have spread more easily -- the reason we need social distancing now -- but it doesn't automatically mean it has to do with raw meat of exotic animals. Now, it can be the problem is raw meat after all! But it seems to me research is still ongoing about whether this was the real culprit. That's all I'm saying.

otfc321 7y ago

Supporting the the continued lockdown is not only unamerican and illegal but it is also RACIST. All the H1-Bs in California are going to be screwed within another month. Hope you like being racists you liberals!

clarkevans 7y ago

> Does the amount of virus exposure affect disease severity? It looks that way. Besides reducing the transmission rate, social distancing measures could also be reducing the initial viral load of each exposure, leading to milder disease profiles, lowering population hospitalization and fatality rates.

eveningcoffee 7y ago

Some people have tried to infer SARS-CoV-2 severity based on common corona viruses https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102597 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7102597 (currently hospitalized 89998, CFR so far in hospitals 17%). But, it does not mean that the question is wrong of course and it is an interesting piece. Also Sweden is not having some clever strategy. Anders Tegnell messed up so bad that they had to claim it to be a strategy https://www.project-syndicate.org/commentary/swedish-coronavirus-no-lockdown-model-proves-lethal-by-hans-bergstrom-2020-04 https://www.project-syndicate.org/commentary/swedish-coronav...

toolz 7y ago
Why does it seem like both sides seem to be so sensationalist about Sweden. They have middle of the road all-cause mortality and most recently their sero studies suggest an extremely low IFR but that got pulled due to bad randomization of test subjects so that might go up to middle of the road for Europe for Sweden too. They haven't performed great and not poorly either. It's strange to see people so polarized over them.
- tigershark 7y ago
  Because they should be compared with the neighbouring Nordic countries. Norway 38 deaths/M Finland 37 deaths/M Denmark 76 deaths/M Sweden 244 deaths/M It’s an order of magnitude more deaths per million than Norway or Finland.
  - adamiscool8 7y ago
    But isn't that the point? They accepted more deaths up front, but over the long-run those countries should average out about the same per capita, while Sweden avoided immediate negative social/economic impacts.
    - twic 7y ago
      Perhaps. Hopefully! It's too early to know the final counts, though, which is why there is still scope for controversy.

hristov 7y ago

I think everybody should carefully read the short section that says "Does the amount of exposure affect the severity?". Some people are looking at antibody studies that show that large parts of the population are somehow affected and then doing back of the napkin math and deciding that this is really not worse than the flu in terms of death rate. They are further encouraged by the fact that people that die tend to be older and with pre-existing conditions. Then they say we should open everything up and get everything "back to normal", and sometimes they add that this is just a way to winnow out the old and the weak. As problematic as the latter statement is, the above thinking is actually dangerously optimistic. Experience shows us that in specific situations with prolonged/repeated exposure, the death rates are much higher. Also young and healthy people may get seriously sick and die due to high level of exposure. This has already been happening in hospitals that did not have sufficient protective equipment/procedures. If we open everything up and get into a situation where the virus is all over the place we can get into a horrible spiral of increased exposure and increased death rates etc.

Bnshsysjab 7y ago
As someone who hasn’t followed, and I understand I’m asking a random internet user this and not a scientist, but what is the definition of ‘prolonged exposure?’ Are people who contract the disease less likely to die that someone who is in close contact for a prolonged period of time? How long is that period? 15 minutes? Two hours?
- bdamm 7y ago
  To wit; if my wife gets sick and I care for her, does that mean I am experiencing "prolonged exposure"?
  - tomrod 7y ago
    Yes.
  - code_duck 7y ago
    Being around a positive person continually for several days at home would mean a lot more exposure than many people would get when encountering others in public.

softwarejosh 7y ago

maybe all the permenant lung damage will pave way for stem cell researchers and well finally get something done

mattkrause 7y ago
If you’re not a biologist, it may have flown under the radar that there’s quite a bit of stem cell work going on already. The development of induced pluripotent stem cells (iPSCs), which can be made from adult tissue rather than embryos, sorta sidestepped much of the ethical debate. They’re not exactly equivalent, but iPSCs have opened the door to a lot of exciting research because you can culture tissue that’s very similar to a patient’s. A few clinical trials were starting to get underway too....

known 7y ago

Q: How close we are to achieving herd immunity? A: To achieve herd immunity we need 60-70% of the population to carry antibodies to the virus. The results of antibody tests suggest that in Europe and the US, in general, we are in the low single digits https://archive.vn/UEgL5 https://archive.vn/UEgL5

agildehaus 7y ago
Herd immunity threshold is (R0−1)/R0. CDC pegs R0 at 5.7 with a CI of 95%. (5.7-1)/5.7 = 82% https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article?deliveryName=USCDC_333-DM25287 https://wwwnc.cdc.gov/eid/article/26/7/20-0282_article?deliv...
- saalweachter 7y ago
  Oof, that's an increase over previous estimates of R0.

dr_ 7y ago

It should be noted, with respect to acquiring immunity, that with SARS-CoV(1), the amount of time after which immunity theoretically could be lost would be => 3 years. If SARS-COV-2 offers a similar level of immunity, that may not be a ton of time, but its not insignificant either, especially if a vaccine could be developed within that time frame.

Navedkhann 7y ago

The theory of using Famotidine for COVID-19 has been thoroughly explained in the following articles: https://preprints.jmir.org/preprint/19199 https://preprints.jmir.org/preprint/19199 https://preprints.jmir.org/preprint/19583 https://preprints.jmir.org/preprint/19583?