7 ms·

1. Is it possible to get COVID-19 twice? No, doesn't seem to be, but you might still have "viral shedding" for a bit even after you are "recovered". meaning yo

• sutterbomb 7y ago
  Is Qatar hot and dry? I think heat with humidity are more likely to dampen the spread compared to just heat
  • cptskippy 7y ago
    > I think heat with humidity are more likely to dampen the spread compared to just heat That's odd to me because I associate warm and wet with uncleanliness and festering cesspools.
    • thisisnico 7y ago
      Welcome to living anywhere near the great lakes in summertime.
    • syllogism 7y ago
      This outbreak has made me realise how I've gone my whole adult life without knowing some basic things about bacteria and viruses. Like, I never knew about how soap dissolves the virus's outer coating... Anyway apparently hot and wet is good for bacteria, but cold is better for viruses. The bit that made it click for me is that viruses aren't metabolising anything outside of the host-cell, so the best a virus can hope for is to not be destroyed -- and cold is a better preservative. I'm still not sure whether hot and humid is better than hot and dry though? I think I read that hot and dry is worse, because it increases evaporation.
      • ch4s3 7y ago
        > I never knew about how soap dissolves the virus's outer coating That's not true for every type of virus, but it is true for corona viruses.
    • lonelappde 7y ago
      Humidity makes flu less contagious, likely because something about the wet heavy air deactivates airborne viruses. https://www.google.com/amp/s/www.livescience.com/amp/27533-flu-transmission-humidity.html https://www.google.com/amp/s/www.livescience.com/amp/27533-f...
  • aliswe 7y ago
    Dunno about Qatar but in Abu Dhabi humidity has reached 100%
    • jacobush 7y ago
      Relative
  • chipsa 7y ago
    Qatar is more humid than people think for being a desert country, because it is a peninsula in the gulf. As I write this, it's about 70% relative humidity.
• bilbo0s 7y ago
  I wonder? I know that in places like Qatar and India, there is a tendency to use artificial cooling. (I'm pretty sure India is the single biggest growth market for air conditioning on the planet.) I'm just thinking, if a bunch of people gather in an air conditioned theater, would it even matter if it was 95 degrees outside? Just a thought. I guess to really know, we'd have to wait and see what happens in places where it is hot, and humid, and artificial cooling is not so widespread? Like Sub-Saharan Africa.
• iforgotpassword 7y ago
  (Not a doctor.) In general it is possible to get the same infection twice, depending on circumstances like a weak immune system, not recovering properly after the first one etc. Whether this is true for ncov is most likely not scientifically proven yet, but even if, it is safe to assume that this happening is the exception.
• dyingkneepad 7y ago
  Also Brazil: cases are starting to exponentially grow, and it's summer there and super hot. Even hotter cities like Brasilia are having cases.
• deleted 7y ago
  [deleted]
• David 7y ago
  Can you cite some sources for your responses to 1 and 4? Re: 5, there's clearly a distinction between typical mutations, which have no particular effect on the virus' behavior but do allow us to trace infections, and behavioral mutations, which might allow reinfection or make the virus more or less contagious or deadly. I think GP is asking about the second kind, since they're also asking about reinfection. Maybe that's obvious, but considering that, are there sources saying that the evidence so far is that there is only one strain? Re 6: this is an interesting question. My layman's understanding is that heat usually reduces the spread of disease in temperate climates both because the disease can't survive as well and because people spend more time outdoors and in less people-dense spaces. In somewhere really hot like Qatar, we would expect to see the opposite of the second effect; I'd think people would spend more time indoors with A/C when it's excessively hot outside, increasing transmission rates as the outside temperature rises.
• throwaway_pdp09 7y ago
  "it's hot [in Qatar]." I used to live in that part of the world. Air conditioning and active cooling is pervasive there. In a sense, people's exposure to the overwhelming heat of the day is perhaps much more limited than you might expect. There are surprisingly few cases in Africa (https://www.newscientist.com/article/2236760-we-dont-know-why-so-few-covid-19-cases-have-been-reported-in-africa/ https://www.newscientist.com/article/2236760-we-dont-know-wh...) and Africa is a poorer continent in general, and perhaps aircon is much more limited there than that area of Arabia. Maybe there's a link.
  • teruakohatu 7y ago
    There could be less testing in Africa, so less confirmed cases. Here in New Zealand we have had only 5 cases with no increase in days, yet very close links to China and Australia and cool fall weather, making me wonder if and how many undiagnosed cases there are.
    • thedudeabides5 7y ago
      Best papers I've seen on the weather - virus link so far https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3550308 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3550308
    • Cybiote 7y ago
      The case fatality rate is estimated at 2% - 3% but that is with medical care. Without ventilators and ICU care, CFR might rise to as high as 10%-15%. With its exponential growth rate, it'd be highly surprising for the virus to go unnoticed so long.
      • sgslo 7y ago
        Do you have a source for the '10%-15%' value? If not, I'd encourage you to not spread FUD.
• gus_massa 7y ago
  >> 5. What's the likelihood that a mutation will occur once treatment is more widespread? > Mutations occur all the time, there are already 10's of known mutations of virus, it doesn't mean there are 10 separate diseases. I agree, but I'd like to add more details. Most mutations are irrelevant, and if you have antibodies for the original version, the same antibody is useful for the new version. From time to time, the mutation is in the part that encodes the part that is recognized by the antibody, and then you may be infected by the new version. [There are a lot of other mutations. A lot of mutations just make the virus not able to reproduce, or break some important part, so the mutated version just disappear. Another mutations make the virus more effective or less effective, so they change how bad the symptoms are.]
  • vanniv 7y ago
    Others may change how fatal the infection is (in either direction) This is actually one of the reasons that viruses generally become less deadly the longer they circulate through a population. A less-deadly version will spread faster (by not killing it's hosts), and will tend to outcompete a deadlier version
• nostromo 7y ago
  Flu viruses don’t spread less when it’s warm. They spread less when it’s more humid. For the northern hemisphere it’s much less humid in winter, but that’s not true everywhere. https://www.livescience.com/27533-flu-transmission-humidity.html https://www.livescience.com/27533-flu-transmission-humidity.... We really should be increasing humidity in hospitals and offices in the winter. Newer planes have already been moving in that direction (to increase comfort).
  • bumby 7y ago
    I believe the flu virus is susceptible to UV exposure which may correlate to warmer weather? As explained to me by an M.D. this is why flu infections go down in the summer
  • nedwards72756 7y ago
    Also, spreading of flu during "flu season" is marked by holidays when long distance travel happens. This causes slightly different strains of the flu to be brought into regions where people do not have a natural defense to that strain.
    • aquadrop 7y ago
      There is a lot of long distance traveling during summer as well, with all the vacations.
    • slowmovintarget 7y ago
      Interesting tidbit I learned at a Town Meeting (streamed) yesterday. Winter Break in Massachusetts was instituted to halt the rapid spread of flu during the winter months. Kids would take it into school, spread it among themselves and bring it home to adults, who would get hit harder by it. The winter break put an an incidental isolation in place that slowed the person-to-person spread down. This is why schools have to close now to control the spread of COVID-19.
      • cvwright 7y ago
        I think you mean February break. Winter break usually refers to the break that includes Christmas and New Years Day. In Massachusetts they instituted a second break in February, in addition to spring break in April, in order to cut the flu season.
• blauditore 7y ago
  Regarding Quatar (or any warm/hot place): Note that a significant fraction of people spends a lot of time inside. This means the temperature there is actually colder, there's less sunlight (especially UV), and people are closer to each other. Also note that for the common cold, the reason that it spreads more during winter times is not primarily temperature, but the fact that people spend more time inside while ventilating (opening windows) less often. Comparing speed of distribution in different countries is extremely difficult, as there are too many factors at play. The 258 cases in Qatar might have been 500 if it was colder there, no one can proof or refute that.
  • richardw 7y ago
    > The 258 cases in Qatar might have been 500 if it was colder there, no one can proof or refute that. It certainly means hot weather won’t “stop” the virus, just slow it by (in your example) 50%. That’s not a lot of comfort, although it would buy some time.
• stronglikedan 7y ago
  All I've heard regarding #1 thus far is "we don't know". Do you have source that states otherwise? Based on the responses so far, I'm not alone in wanting to review it.
• mullingitover 7y ago
  > 6. Does the heat make it significantly less likely for you to get COVID-19? There is actually another part of the world where it's summer. Australia's case count graph is displaying the standard hockey stick shape, so based on the typical growth rate we should know in a week or two.
• slightwinder 7y ago
  > A good counterpoint is Qatar adding 258 cases in one day, it's hot there. Not this week. Temperature is below 30° celsius, more around 20°. Summer has yet to come.
• thinkingemote 7y ago
  While there is evidence that viruses don't like heat, the main argument about wanting to flatten the peak until the warmer months is because the colder months also have correlation to other diseases. This disease would spread the same in any weather but most countries would be able to cope better, hospitals have more space and people's immune systems would be stronger in the summer.
• Ar-Curunir 7y ago
  It's also still Spring-ish in Qatar, so not quite as hot as it can get.
• rhinokungfu 7y ago
  As per this paper - https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767 https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767. Both increase in temperature and humidity reduces the transmission of COVID-19. Abstract: This paper investigates how air temperature and humidity influence the transmission of COVID-19. After estimating the serial interval of COVID-19 from 105 pairs of the virus carrier and the infected, we calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of non-intervened transmission intensity, we find, under a linear regression framework for 100 Chinese cities, high temperature and high relative humidity significantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities. One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively. This result is consistent with the fact that the high temperature and high humidity significantly reduce the transmission of influenza. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19.
  • hiq 7y ago
    Related HN thread: https://news.ycombinator.com/item?id=22563932 https://news.ycombinator.com/item?id=22563932
  • bumby 7y ago
    Doctors tend to be reluctant to extrapolate strong conclusions from relatively close R0 values like those presented because of the number of confounding factors. It’s really most valuable when looking at orders of magnitude difference (e.g., measles with an R0 of around 15 compared to seasonal flu with an R0 of around 1-3). I didn’t see in that study much consideration of other variables and the p-value used for relative humidity was on the high side by publication standards (up to 10%)
• fractal618 7y ago
  If it's mutating, would it be better to get the virus early, before it mutates to something more severe?
  • dukha 7y ago
    Typically viruses mutates to less severe variants because it allows them to infect more people.
    • scotty79 7y ago
      I think this is true for very lethal viruses that have risk of killing host before spreading. For virus that can spread before any symptoms and long after symptoms disappear and survive so long on the objects and in the air I think there will be no evolutionary pressure to get milder. And we can get harsher version just by random chance because this virus is so infectious that it has a lot of leniency whether and when to kill the host.
  • Zancarius 7y ago
    Mutating doesn't mean it's going to get worse. It's entirely possible for the virus to mutate into a less dangerous form. Going out of your way to get it now is too much of a risk. While I don't believe SARS-CoV-2 is quite as bad as the media frenzy is making it out to be, it's absolutely a good idea to do everything you can to avoid getting it. The same goes for the flu and for colds. If you catch any of these, you may be OK, but you risk spreading it to people who won't be.
    • NortySpock 7y ago
      1-3% case fatality rate? 70% of the population expected to be infected. That's ~1 out of every 100 people. This isn't just a media frenzy, by the end of this you WILL know someone who died as a result of (complications of) Coronavirus.
      • zadler 7y ago
        And yet a lot of countries seem to have controlled it to a great extent. China, South Korea, japan, Singapore. They’re not showing explosive numbers.
• sbmthakur 7y ago
  Do high humidity levels decrease potency in case of Coronavirus?
• LinuxBender 7y ago
  Here are some of the mutations / strains [1] [1] - https://nextstrain.org/ncov https://nextstrain.org/ncov
• dwnvoted2hell 7y ago
  "4. There's evidence that there are multiple strains, can you get both strains? You shouldn't think about them as multiple strains, as of now it is 1 disease." There have already been 2 confirmed strains, so I don't know where you're getting your info from.