7 ms·

I've read that asymptomatic carriers are though to be less infectious than those with symptoms because of the lower concentration of virus in the saliva. Also,

I've read that asymptomatic carriers are though to be less infectious than those with symptoms because of the lower concentration of virus in the saliva. Also, many virologists mentioned in recent texts that the initial concentration of the virus you receive can affect how sick you'll get - the more viruses you're exposed to, the faster they can invade the body and the more severe it will get. Can those two facts be combined into a theory that asymptomatic carriers are more likely to produce more mild and asymptomatic cases? Don't know if it makes any sense (probably not), but it would certainly explain how in some closed environments there's a prevalence for mild cases, while in others there's a plenty of very sick people, regardless of the age.

toshk 6y ago
These were exactly the assumptions of the RIVM in the Netherlands end Februari and March causing it to completely spiral out of control.
- johnchristopher 6y ago
  > Rijksinstituut voor Volksgezondheid en Milieu > Netherlands National Institute for Public Health and the Environment > The Netherlands National Institute for Public Health and the Environment, is a Dutch research institute that is an independent agency of the Dutch Ministry of Health, Welfare and Sport. RIVM performs tasks to promote public health and a safe living environment by conducting research and collecting knowledge worldwide.
- Peter-Jan 6y ago
  > causing it to completely spiral out of control. I live in the Netherlands and I think you could say that we actually have it quite under control (relatively speaking of course). We never reached peak ICU capacity and the ICU occupancy has been steadily declining for more than two weeks now[1]. Our schools for children between the ages of 4 and 12 are scheduled to partially open again on the 11th of may[2]. [1] https://nos.nl/artikel/2331720-coronacijfers-van-25-april-rivm-ziet-nog-altijd-dalende-lijn.html https://nos.nl/artikel/2331720-coronacijfers-van-25-april-ri... [2] https://nos.nl/artikel/2331460-kabinet-wil-basisscholen-voor-zomer-weer-helemaal-open.html https://nos.nl/artikel/2331460-kabinet-wil-basisscholen-voor...
  - toshk 6y ago
    We, the Netherlands, got it under control because we went into stricter lockdown against the advice of the RIVM. Above assumptions led to advice against a lockdown. Only under pressure of the IC doctors on Sunday the 15th of march did the prime minister close all schools and restaurants. (A high school is like a festival every day) The policy and advice of RIVM has been wrong and misleading from the end of February. For many of us it was already clear they lost control beginning of March. There was one hero in the North of the Netherlands who went against RIVM and the Minister of health: https://eenvandaag.avrotros.nl/item/het-gelijk-van-microbioloog-alex-friedrich-testen-testen-testen-krijgt-nu-landelijk-navolging/ https://eenvandaag.avrotros.nl/item/het-gelijk-van-microbiol.... This article in the Volkskrant describes how the RIVM was panicking beginning of March, but the prime minister wanted to present "good weather", and they also send their stock of masks to China beginning februari: https://www.volkskrant.nl/nieuws-achtergrond/nederland-stuurde-in-februari-ondanks-who-waarschuwing-miljoenen-medische-hulpmiddelen-naar-china~b15ecd46/ https://www.volkskrant.nl/nieuws-achtergrond/nederland-stuur... Even now they are not testing healthcare people with symptoms in elderly homes and also not providing any sort of masks. Claiming the available masks are not of sufficient quality, they prefer to send healthcare people to work without masks then to get high quality masks even if it is without the preferred certificate. Last point. Under control is relative. The IC capacity reached a higher number then we ever anticipated, still more IC beds are occupied by corona patients then we had in total beginning of 2020. https://stichting-nice.nl/ https://stichting-nice.nl/ For most of the hospitals in the Netherlands most operations and treatments are still postponed. For instance for many cancer patients the date of their treatment is still not sure: https://www.volkskrant.nl/nieuws-achtergrond/chemo-uitgesteld-transplantatie-afgeblazen-in-de-ziekenhuizen-voltrekt-zich-een-schaduwcrisis~b9d4efb4/ https://www.volkskrant.nl/nieuws-achtergrond/chemo-uitgestel...
    - The_Double 6y ago
      The data doesn't support any of this. Overlaying the R0 estimation and the date that interventions were taken shows that the original "stay home when sick, wash hands and don't shake" advise had the biggest effect. This also matches most research that has been done on influenza. The lockdown on schools and restaurants had a much lower effect.https://www.volkskrant.nl/nieuws-achtergrond/corona-onder-controle-krijgen-zijn-we-misschien-te-voorzichtig~beac33ff/ https://www.volkskrant.nl/nieuws-achtergrond/corona-onder-co...
ck2 6y ago
how do you ever make antibodies if you are perpetually asymptomatic though? do you carry it forever? does it attack eventually? what happens if you are an asymptomatic carrier and get a vax?
- darkwater 6y ago
  AFAIK asymptomatic means you show no symptoms but your body fights and creates antibodies just the same. Disclaimer: I'm not a doctor.
- venning 6y ago
  "Typhoid Mary" was an asymptomatic carrier of typhoid fever for at least 38 years. https://en.wikipedia.org/wiki/Mary_Mallon https://en.wikipedia.org/wiki/Mary_Mallon
  - pbhjpbhj 6y ago
    FWIW I think that article shows her infecting people for only 15 years (1900-1915), then being quarantined for a further 23.
    - auntienomen 6y ago
      A post-mortem confirmed that her gallbladder was loaded with the bacteria that cause typhoid.
      - Drdrdrq 6y ago
        Wikipedia mentions that autopsy might not have been performed.
    - venning 6y ago
      The Wikipedia article doesn't cover everything. Reference for the sibling comment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959940/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959940/
jbritton 6y ago
I have been wondering about the effect of the degree of initial infection. I kind of assume the virus grows exponentially inside the body and would dwarf the initial constant. If a low initial dose affects the severity of the disease, I think that would be incredibly useful to know. I also wish there was info on percentage of infection via fomites vs inhalation.
- fermienrico 6y ago
  I think it’s the opposite. The initial conditions have a profound effect on the exponential nature of the growth. Half the dose could mean that your immune system can suppress it. There is probably critical rate at which both growth rates match.
  - fermienrico 6y ago
    I don't think my response is 100% correct. The rate of change (derivative) of an exponetial function is another exponential function. d/dx(2^x) = (2^x)*ln(2). And if the base is e, then d/dx(e^x) = e^x.
    - fermienrico 6y ago
      Yo people, I don't understand why my statements are correct - please someone with a math background or an epidemiologist comment here, I suck at math and I don't understand how these growth rates compare. My comment is being upvoted but it may not be true.
      - bsmith89 6y ago
        Under the exponential growth model, the increased incubation time (before you hit the same total population size) is inversely proportional to the log of the initial dose, so (e.g.) 1/100th of the initial dose gives you only ~7 (log2(100) = 6.64) additional doubling times before arriving at the same population size. While this is not insignificant, it does mean that initial dose is potentially much less important than sources of variability that affect the in-host doubling time. Edited to add: Here's a preprint that is relevant to the "initial dose vs. immune system response" thought: <https://www.medrxiv.org/content/10.1101/2020.03.26.20044487v1.full.pdf> https://www.medrxiv.org/content/10.1101/2020.03.26.20044487v...
frereubu 6y ago
Where did you read that? Superficially that might make sense - less virus particles == less obvious symptoms - but there are a wide variety of virus responses that show virulence and infectiousness aren't necessarily correlated. If anyone wants to read more about this I can't recommend highly enough the book Spillover by David Quammen, which was published in 2012, and covers zoonotic (animal-to-human transmission) viruses, including SARS. Reading the section on SARS made the hairs on the back of my neck stand up. It's uncannily similar to what's happening with Covid-19, and explains a lot of the background involved in these kinds of viruses.
- ketzo 6y ago
  I actually do remember reading that this was true specifically in the case of COVID — that more exposure so far seems to correlate with a worse infection. Sadly, I have no idea where I read this. But... I know I did! Recently! Maybe NYT?
  - ScottBurson 6y ago
    Yeah, I saw it too. The hypothesis, as I recall, is that the more virions inhaled, the more likely some of them will get deep in the lungs where they can do the most damage.
    - phkahler 6y ago
      I read something like that too. I came away thinking that ingestion might be a better way to get it than inhalation. I think you really need to keep it out of the lungs and nervous system. But that's all my impression from who knows where.
  - snowmaker 6y ago
    This is the article you meant: https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral...
- netcan 6y ago
  Bucheight
sandworm101 6y ago
>> Also, many virologists mentioned in recent texts that the initial concentration of the virus you receive can affect how sick you'll get - the more viruses you're exposed to, the faster they can invade the body and the more severe it will get. That is basic infections 101. When you are exposed to any dangerous virus a race starts between the virus and your immune system. If the virus starts out only infecting a handful of cells, your immune system has a head start in developing antibodies before symptomatic infection sets in. (This is also a basic principle behind many vaccines.) But if you are hit will a massive viral load that instantly infects every cell in your lungs, the immune system is fighting uphill from day one. A massive initial viral exposure can also trigger an excessive immune response, for instance dangerously high fever. Such an immune response can be as deadly as the virus. Much covid research is going into not defeating the virus directly but regulating/slowing the immune response to the patient survives their own immune response. This principal explains why healthcare workers are suffering so. They are exposed to constant massive doses of virus, possibly from multiple patients carrying slight different versions of the virus. So they get sicker than people who are exposed in the general community.
- throwaway7614 6y ago
  Sleep deprivation and extreme stress could be factors that affect healthcare workers (1) https://theconversation.com/coronavirus-does-the-amount-of-virus-you-are-exposed-to-determine-how-sick-youll-get-135119 https://theconversation.com/coronavirus-does-the-amount-of-v...
- dima_medvedev 6y ago
  There's already a comment above pointing out that it might be the initial infection location plays big role. Seems very likely that poor ventilation (in e.g. medical facilities) is main cause of severe cases. Also, the virus is replicating exponentially only if it can reach many uninfected cells. It takes ~10 hours for an infected cell to start producing virus. Not sure whether non-specific immune system can somehow "contain" virus, would be great to learn about that.
Symmetry 6y ago
It depends. If you're not going to develop symptoms for another 14 days then yeah, you're not infectious. But for a few days before symptom onset you become just as infectious as you will be after symptom onset - which is one of the things that makes this virus hard to stop. A low initial dose doesn't seem to affect the course of the infection much, though. For a sufficiently low dose either none of the viruses find an ACE2 receptor or your innate immune system wipes up the virus without you noticing (as it does for you with other viruses every day). There's some evidence that particularly high doses can cause particularly bad prognoses. We have pretty good evidence that this is the case with measles. There's very anecdotal evidence suggesting that maybe this is the case with SARS-CoV-2. But it looks like low doses lead to a chance of no infection, not a chance of an asymptomatic one.
- greedo 6y ago
  I'm very confused by this as I understand that asymptomatic patients are infectious. How does this square with your second sentence?
  - Symmetry 6y ago
    So, it looks like most asymptomatic infections later become infectious. Basically every person who gets symptoms had a multi-day asymptomatic infectious period they went through. SARS-CoV-2 does a better job than most of avoiding the automatic immune system because its large genome lets it encode a bunch of proteins that aren't for making new viruses but rather screwing with the immune system in ways that let it reach high numbers before the immune system catches on. Every virus that can actually make you sick does this but SARS-CoV-2 seems better than most. But frequently you're able to fight off the infection at a later point before the part of the automatic immune system reaction that makes you feel sick kicks into play but after you're got a chance to infect other people. The normal course of the automatic immune system wiping out an invading pathogen without you noticing is that it happens immediately without you noticing and you never get a chance to infect anyone. But if that doesn't happen for COVID-19 or influenza or most things there'll be a time period after infection but before you notice anything where you're infectious. For COVID-19 this period is particularly infectious compared to the flu or SARS-1 or most things. It might be that flu and other coronaviruses tend to people who are infected enough to transmit the virus but never go on to develop symptoms. I don't know in that case.
SilasX 6y ago
I remember Robin Hanson [1] used the second fact to recommend "variolation", injecting everyone with a tiny amount of the virus so that they'll get the immunity without the sickness (making it a "natural vaccine"). [1] http://www.overcomingbias.com/2020/03/variolation-may-cut-covid19-deaths-3-30x.html http://www.overcomingbias.com/2020/03/variolation-may-cut-co...
jedimastert 6y ago
I would think they'd be less infectious simply because they don't have symptoms that make them more so, namely coughing and sneezing and the like.
heisenbit 6y ago
Prof. Dr. Drosten (inventor of Covid-19 test) said in the interview below that there is a study which shows asymptomatic adult shed as much virus as symptomatic ones. He also said there is no good study on how many viruses are shed by kids. https://tvthek.orf.at/profile/Additional-Content/1670/Langfassung-Interview-mit-Virologe-Christian-Drosten/14049580 https://tvthek.orf.at/profile/Additional-Content/1670/Langfa...

toshk 6y ago

These were exactly the assumptions of the RIVM in the Netherlands end Februari and March causing it to completely spiral out of control.

johnchristopher 6y ago
> Rijksinstituut voor Volksgezondheid en Milieu > Netherlands National Institute for Public Health and the Environment > The Netherlands National Institute for Public Health and the Environment, is a Dutch research institute that is an independent agency of the Dutch Ministry of Health, Welfare and Sport. RIVM performs tasks to promote public health and a safe living environment by conducting research and collecting knowledge worldwide.
Peter-Jan 6y ago
> causing it to completely spiral out of control. I live in the Netherlands and I think you could say that we actually have it quite under control (relatively speaking of course). We never reached peak ICU capacity and the ICU occupancy has been steadily declining for more than two weeks now[1]. Our schools for children between the ages of 4 and 12 are scheduled to partially open again on the 11th of may[2]. [1] https://nos.nl/artikel/2331720-coronacijfers-van-25-april-rivm-ziet-nog-altijd-dalende-lijn.html https://nos.nl/artikel/2331720-coronacijfers-van-25-april-ri... [2] https://nos.nl/artikel/2331460-kabinet-wil-basisscholen-voor-zomer-weer-helemaal-open.html https://nos.nl/artikel/2331460-kabinet-wil-basisscholen-voor...
- toshk 6y ago
  We, the Netherlands, got it under control because we went into stricter lockdown against the advice of the RIVM. Above assumptions led to advice against a lockdown. Only under pressure of the IC doctors on Sunday the 15th of march did the prime minister close all schools and restaurants. (A high school is like a festival every day) The policy and advice of RIVM has been wrong and misleading from the end of February. For many of us it was already clear they lost control beginning of March. There was one hero in the North of the Netherlands who went against RIVM and the Minister of health: https://eenvandaag.avrotros.nl/item/het-gelijk-van-microbioloog-alex-friedrich-testen-testen-testen-krijgt-nu-landelijk-navolging/ https://eenvandaag.avrotros.nl/item/het-gelijk-van-microbiol.... This article in the Volkskrant describes how the RIVM was panicking beginning of March, but the prime minister wanted to present "good weather", and they also send their stock of masks to China beginning februari: https://www.volkskrant.nl/nieuws-achtergrond/nederland-stuurde-in-februari-ondanks-who-waarschuwing-miljoenen-medische-hulpmiddelen-naar-china~b15ecd46/ https://www.volkskrant.nl/nieuws-achtergrond/nederland-stuur... Even now they are not testing healthcare people with symptoms in elderly homes and also not providing any sort of masks. Claiming the available masks are not of sufficient quality, they prefer to send healthcare people to work without masks then to get high quality masks even if it is without the preferred certificate. Last point. Under control is relative. The IC capacity reached a higher number then we ever anticipated, still more IC beds are occupied by corona patients then we had in total beginning of 2020. https://stichting-nice.nl/ https://stichting-nice.nl/ For most of the hospitals in the Netherlands most operations and treatments are still postponed. For instance for many cancer patients the date of their treatment is still not sure: https://www.volkskrant.nl/nieuws-achtergrond/chemo-uitgesteld-transplantatie-afgeblazen-in-de-ziekenhuizen-voltrekt-zich-een-schaduwcrisis~b9d4efb4/ https://www.volkskrant.nl/nieuws-achtergrond/chemo-uitgestel...
  - The_Double 6y ago
    The data doesn't support any of this. Overlaying the R0 estimation and the date that interventions were taken shows that the original "stay home when sick, wash hands and don't shake" advise had the biggest effect. This also matches most research that has been done on influenza. The lockdown on schools and restaurants had a much lower effect.https://www.volkskrant.nl/nieuws-achtergrond/corona-onder-controle-krijgen-zijn-we-misschien-te-voorzichtig~beac33ff/ https://www.volkskrant.nl/nieuws-achtergrond/corona-onder-co...

ck2 6y ago

how do you ever make antibodies if you are perpetually asymptomatic though? do you carry it forever? does it attack eventually? what happens if you are an asymptomatic carrier and get a vax?

darkwater 6y ago
AFAIK asymptomatic means you show no symptoms but your body fights and creates antibodies just the same. Disclaimer: I'm not a doctor.
venning 6y ago
"Typhoid Mary" was an asymptomatic carrier of typhoid fever for at least 38 years. https://en.wikipedia.org/wiki/Mary_Mallon https://en.wikipedia.org/wiki/Mary_Mallon
- pbhjpbhj 6y ago
  FWIW I think that article shows her infecting people for only 15 years (1900-1915), then being quarantined for a further 23.
  - auntienomen 6y ago
    A post-mortem confirmed that her gallbladder was loaded with the bacteria that cause typhoid.
    - Drdrdrq 6y ago
      Wikipedia mentions that autopsy might not have been performed.
  - venning 6y ago
    The Wikipedia article doesn't cover everything. Reference for the sibling comment: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959940/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959940/

jbritton 6y ago

I have been wondering about the effect of the degree of initial infection. I kind of assume the virus grows exponentially inside the body and would dwarf the initial constant. If a low initial dose affects the severity of the disease, I think that would be incredibly useful to know. I also wish there was info on percentage of infection via fomites vs inhalation.

fermienrico 6y ago
I think it’s the opposite. The initial conditions have a profound effect on the exponential nature of the growth. Half the dose could mean that your immune system can suppress it. There is probably critical rate at which both growth rates match.
- fermienrico 6y ago
  I don't think my response is 100% correct. The rate of change (derivative) of an exponetial function is another exponential function. d/dx(2^x) = (2^x)*ln(2). And if the base is e, then d/dx(e^x) = e^x.
  - fermienrico 6y ago
    Yo people, I don't understand why my statements are correct - please someone with a math background or an epidemiologist comment here, I suck at math and I don't understand how these growth rates compare. My comment is being upvoted but it may not be true.
    - bsmith89 6y ago
      Under the exponential growth model, the increased incubation time (before you hit the same total population size) is inversely proportional to the log of the initial dose, so (e.g.) 1/100th of the initial dose gives you only ~7 (log2(100) = 6.64) additional doubling times before arriving at the same population size. While this is not insignificant, it does mean that initial dose is potentially much less important than sources of variability that affect the in-host doubling time. Edited to add: Here's a preprint that is relevant to the "initial dose vs. immune system response" thought: <https://www.medrxiv.org/content/10.1101/2020.03.26.20044487v1.full.pdf> https://www.medrxiv.org/content/10.1101/2020.03.26.20044487v...

frereubu 6y ago

Where did you read that? Superficially that might make sense - less virus particles == less obvious symptoms - but there are a wide variety of virus responses that show virulence and infectiousness aren't necessarily correlated. If anyone wants to read more about this I can't recommend highly enough the book Spillover by David Quammen, which was published in 2012, and covers zoonotic (animal-to-human transmission) viruses, including SARS. Reading the section on SARS made the hairs on the back of my neck stand up. It's uncannily similar to what's happening with Covid-19, and explains a lot of the background involved in these kinds of viruses.

ketzo 6y ago
I actually do remember reading that this was true specifically in the case of COVID — that more exposure so far seems to correlate with a worse infection. Sadly, I have no idea where I read this. But... I know I did! Recently! Maybe NYT?
- ScottBurson 6y ago
  Yeah, I saw it too. The hypothesis, as I recall, is that the more virions inhaled, the more likely some of them will get deep in the lungs where they can do the most damage.
  - phkahler 6y ago
    I read something like that too. I came away thinking that ingestion might be a better way to get it than inhalation. I think you really need to keep it out of the lungs and nervous system. But that's all my impression from who knows where.
- snowmaker 6y ago
  This is the article you meant: https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral-dose.html https://www.nytimes.com/2020/04/01/opinion/coronavirus-viral...
netcan 6y ago
Bucheight

sandworm101 6y ago

>> Also, many virologists mentioned in recent texts that the initial concentration of the virus you receive can affect how sick you'll get - the more viruses you're exposed to, the faster they can invade the body and the more severe it will get. That is basic infections 101. When you are exposed to any dangerous virus a race starts between the virus and your immune system. If the virus starts out only infecting a handful of cells, your immune system has a head start in developing antibodies before symptomatic infection sets in. (This is also a basic principle behind many vaccines.) But if you are hit will a massive viral load that instantly infects every cell in your lungs, the immune system is fighting uphill from day one. A massive initial viral exposure can also trigger an excessive immune response, for instance dangerously high fever. Such an immune response can be as deadly as the virus. Much covid research is going into not defeating the virus directly but regulating/slowing the immune response to the patient survives their own immune response. This principal explains why healthcare workers are suffering so. They are exposed to constant massive doses of virus, possibly from multiple patients carrying slight different versions of the virus. So they get sicker than people who are exposed in the general community.

throwaway7614 6y ago
Sleep deprivation and extreme stress could be factors that affect healthcare workers (1) https://theconversation.com/coronavirus-does-the-amount-of-virus-you-are-exposed-to-determine-how-sick-youll-get-135119 https://theconversation.com/coronavirus-does-the-amount-of-v...
dima_medvedev 6y ago
There's already a comment above pointing out that it might be the initial infection location plays big role. Seems very likely that poor ventilation (in e.g. medical facilities) is main cause of severe cases. Also, the virus is replicating exponentially only if it can reach many uninfected cells. It takes ~10 hours for an infected cell to start producing virus. Not sure whether non-specific immune system can somehow "contain" virus, would be great to learn about that.

Symmetry 6y ago

It depends. If you're not going to develop symptoms for another 14 days then yeah, you're not infectious. But for a few days before symptom onset you become just as infectious as you will be after symptom onset - which is one of the things that makes this virus hard to stop. A low initial dose doesn't seem to affect the course of the infection much, though. For a sufficiently low dose either none of the viruses find an ACE2 receptor or your innate immune system wipes up the virus without you noticing (as it does for you with other viruses every day). There's some evidence that particularly high doses can cause particularly bad prognoses. We have pretty good evidence that this is the case with measles. There's very anecdotal evidence suggesting that maybe this is the case with SARS-CoV-2. But it looks like low doses lead to a chance of no infection, not a chance of an asymptomatic one.

greedo 6y ago
I'm very confused by this as I understand that asymptomatic patients are infectious. How does this square with your second sentence?
- Symmetry 6y ago
  So, it looks like most asymptomatic infections later become infectious. Basically every person who gets symptoms had a multi-day asymptomatic infectious period they went through. SARS-CoV-2 does a better job than most of avoiding the automatic immune system because its large genome lets it encode a bunch of proteins that aren't for making new viruses but rather screwing with the immune system in ways that let it reach high numbers before the immune system catches on. Every virus that can actually make you sick does this but SARS-CoV-2 seems better than most. But frequently you're able to fight off the infection at a later point before the part of the automatic immune system reaction that makes you feel sick kicks into play but after you're got a chance to infect other people. The normal course of the automatic immune system wiping out an invading pathogen without you noticing is that it happens immediately without you noticing and you never get a chance to infect anyone. But if that doesn't happen for COVID-19 or influenza or most things there'll be a time period after infection but before you notice anything where you're infectious. For COVID-19 this period is particularly infectious compared to the flu or SARS-1 or most things. It might be that flu and other coronaviruses tend to people who are infected enough to transmit the virus but never go on to develop symptoms. I don't know in that case.

SilasX 6y ago

I remember Robin Hanson [1] used the second fact to recommend "variolation", injecting everyone with a tiny amount of the virus so that they'll get the immunity without the sickness (making it a "natural vaccine"). [1] http://www.overcomingbias.com/2020/03/variolation-may-cut-covid19-deaths-3-30x.html http://www.overcomingbias.com/2020/03/variolation-may-cut-co...

jedimastert 6y ago

I would think they'd be less infectious simply because they don't have symptoms that make them more so, namely coughing and sneezing and the like.

heisenbit 6y ago

Prof. Dr. Drosten (inventor of Covid-19 test) said in the interview below that there is a study which shows asymptomatic adult shed as much virus as symptomatic ones. He also said there is no good study on how many viruses are shed by kids. https://tvthek.orf.at/profile/Additional-Content/1670/Langfassung-Interview-mit-Virologe-Christian-Drosten/14049580 https://tvthek.orf.at/profile/Additional-Content/1670/Langfa...