# How does Coronavirus play out? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [July 14, 2020, 12:11am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258 "2020-07-14T00:11:13Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![pool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pool/32/4152_2.png) [@pool](https://boards.straightdope.com/u/pool)\ **Post date:** [July 14, 2020, 12:11am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/1 "2020-07-14T00:11:13Z")
It seems there are a few options: 1. Coronavirus could become some endemic scourge that stays with us. 2. Coronavirus becomes seasonal like the flu 3. Coronavirus just sort of disappears and goes away. 4…? 1. Profit Is there some other possibility I am missing? Are there certain scenarios that are the most likely to occur? You ever think this is just Mother Nature’s response to overpopulation that once we reach a certain population pandemics are just inevitable, although compared to the global population there hasn’t been much mortality. ---
**Author:** ![Fretful\_Porpentine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fretful_porpentine/32/2873_2.png) [@Fretful\_Porpentine](https://boards.straightdope.com/u/Fretful_Porpentine)\ **Post date:** [July 14, 2020, 12:44am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/2 "2020-07-14T00:44:16Z")
Isn’t #2 on your list basically a more specific version of #1, rather than a truly different possibility? Anyway, I’m betting on “it sticks around, we continue to get better at treating it and at some point there’s a fairly effective vaccine, but we don’t actually manage to eradicate it, and it will seem a whole lot less scary once it’s no longer new and unknown and everybody in the world isn’t getting it at once.” Basically, a long slow fade into mundanity. ---
**Author:** ![Leaper](https://avatars.discourse-cdn.com/v4/letter/l/4bbf92/32.png) [@Leaper](https://boards.straightdope.com/u/Leaper)\ **Post date:** [July 14, 2020, 1:36am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/3 "2020-07-14T01:36:28Z")
> [@Fretful\_Porpentine](#): > > Isn’t #2 on your list basically a more specific version of #1, rather than a truly different possibility? I assumed that 1 meant that it stays just as fast spreading, wide ranging, and serious in intensity as it does right now. That seems to me really different from option 2; 1 seems more like “what’s going on in Texas now is a possibility and probability forever.” ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [July 14, 2020, 2:51am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/4 "2020-07-14T02:51:34Z")
> **[How the COVID-19 Pandemic Could End](https://www.scientificamerican.com/article/how-the-covid-19-pandemic-could-end1/)** > > Recent epidemics provide clues to ways the current crisis could stop From the article … > The most famous example of this dynamic in modern history was the H1N1 influenza outbreak of 1918–1919. Doctors and public health officials had far fewer weapons than they do today, and the effectiveness of control measures such as school closures depended on how early and decisively they were implemented. Over two years and three waves, the pandemic infected 500 million and killed between 50 million and 100 million. It ended only as natural infections conferred immunity on those who recovered. > > **The H1N1 strain became endemic, an infectious disease that was constantly with us at less severe levels, circulating for another 40 years as a seasonal virus. It took another pandemic—H2N2 in 1957—to extinguish most of the 1918 strain.** One flu virus kicked out another one, essentially, and scientists don’t really know how. So Spanish Flu actually lasted 40 years and it took another virus to extinguish it. Perhaps that is our future with COVID-19. ---
**Author:** ![Fretful\_Porpentine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fretful_porpentine/32/2873_2.png) [@Fretful\_Porpentine](https://boards.straightdope.com/u/Fretful_Porpentine)\ **Post date:** [July 14, 2020, 1:11pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/5 "2020-07-14T13:11:40Z")
Ah, got it. It didn’t even occur to me that anyone would think perpetual-July-2020-Texas was a possibility, since it’s not consistent with how epidemic diseases worked in the _pre_-vaccine era. ---
**Author:** ![elbows](https://avatars.discourse-cdn.com/v4/letter/e/b3f665/32.png) [@elbows](https://boards.straightdope.com/u/elbows)\ **Post date:** [July 14, 2020, 1:46pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/6 "2020-07-14T13:46:38Z")
Why isn’t, ‘An effective vaccine is found.’, on the list? I’m thinking it’s actually the most likely. Of course there is still the anti vax community to deal with, but this pandemic _could_ change some minds, if the waves continue, and deaths escalate. ---
**Author:** ![Slash1972](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slash1972/32/6461_2.png) [@Slash1972](https://boards.straightdope.com/u/Slash1972)\ **Post date:** [July 17, 2020, 3:29pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/7 "2020-07-17T15:29:32Z")
This thread sort of died out, but are there any new thoughts on what will eventually happen? I mean, the current plan seems to be: 1. Institute measures to keep people away from each other and other measures to help stop the spread (masks, etc) 2. Test as many people as possible as fast as possible 3. Isolate and quarantine those that test positive 4. Something… 5. Pandemic over Is Number 4 “Hope we find a vaccine?” Is it “Number of infections drops below X?” “Number of deaths drops below X?” Something else? ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [July 17, 2020, 3:56pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/8 "2020-07-17T15:56:54Z")
> [@elbows](#): > > Why isn’t, ‘An effective vaccine is found.’, on the list? > > I’m thinking it’s actually the most likely. Of course there is still the anti vax community to deal with, but this pandemic _could_ change some minds, if the waves continue, and deaths escalate. And it’s worth adding that the rate of mortality / severe symptoms is low enough that effective immunization of just the most vulnerable people would be hugely beneficial. In other words, vaccination could have a huge impact on the seriousness of the epidemic even if we don’t have to have enough vaccine available or high enough compliance to achieve herd immunity. ---
**Author:** ![PoppaSan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/poppasan/32/189_2.png) [@PoppaSan](https://boards.straightdope.com/u/PoppaSan)\ **Post date:** [July 17, 2020, 6:21pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/9 "2020-07-17T18:21:36Z")
Chicken pox or any other virus referred to as a childhood disease. This one is just burning through the adults now that other diseases did in ancient times. The younger humans seem to be more resilient to it thus it’ll make its rounds through schools every few years as they develop lifelong immunity (if that is in the cards) and not really be an issue for society as a whole. Without an effective vaccine of course. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [July 18, 2020, 1:21am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/10 "2020-07-18T01:21:29Z")
One set of projections with different "if"s by a quite prestigious group that was published [in Science back in May.](https://science.sciencemag.org/content/368/6493/860) > [@](#): > > It is urgent to understand the future of severe acute respiratory syndrome–coronavirus 2 (SARS-CoV-2) transmission. We used estimates of seasonality, immunity, and cross-immunity for human coronavirus OC43 (HCoV-OC43) and HCoV-HKU1 using time-series data from the United States to inform a model of SARS-CoV-2 transmission. We projected that recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave. … > > … If immunity to SARS-CoV-2 is not permanent, it will likely enter into regular circulation > > Much like pandemic influenza, many scenarios lead to SARS-CoV-2 entering into long-term circulation alongside the other human betacoronaviruses (e.g., [Fig. 3, A and B](https://science.sciencemag.org/content/368/6493/860#F3)), possibly in annual, biennial, or sporadic patterns, over the next 5 years (tables S2 to S4). Short-term immunity (~40 weeks, similar to HCoV-OC43 and HCoV-HKU1) favors the establishment of annual SARS-CoV-2 outbreaks, whereas longer-term immunity (2 years) favors biennial outbreaks. … > > … If immunity to SARS-CoV-2 is permanent, the virus could disappear for 5 or more years after causing a major outbreak > > Long-term immunity consistently led to effective elimination of SARS-CoV-2 and a lower overall incidence of infection. … > > … Low levels of cross-immunity from the other betacoronaviruses against SARS-CoV-2 could make SARS-CoV-2 appear to die out, only to resurge after a few years > > Even if SARS-CoV-2 immunity only lasts for 2 years, mild (30%) cross-immunity from HCoV-OC43 and HCoV-HKU1 could effectively eliminate the transmission of SARS-CoV-2 for up to 3 years before a resurgence in 2024, as long as SARS-CoV-2 does not fully die out … > > … If immunity to SARS-CoV-2 wanes in the same manner as related coronaviruses, then recurrent wintertime outbreaks are likely to occur in coming years. The total incidence of SARS-CoV-2 through 2025 will depend crucially on this duration of immunity and, to a lesser degree, on the amount of cross-immunity that exists between HCoV-OC43/HCoV-HKU1 and SARS-CoV-2. … > > … One-time social distancing efforts may push the SARS-CoV-2 pandemic peak into the autumn, potentially exacerbating the load on critical care resources if there is increased wintertime transmissibility. … ---
**Author:** ![Kimera757](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kimera757/32/3765_2.png) [@Kimera757](https://boards.straightdope.com/u/Kimera757)\ **Post date:** [July 18, 2020, 1:40am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/11 "2020-07-18T01:40:55Z")
I read a few reports that people who get sick only express antibodies for a short period of time (suggesting herd immunity wouldn’t work). I don’t think I’ve heard of a coronavirus doing that before. I’m hoping this is just hyperbole. Then again, I keep hearing that it can infest many parts of the body. Ugh. I’m coming across this even though I have generally not tried to follow the virus, simply because there are so many articles in places like Google News. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [July 19, 2020, 1:27pm UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/12 "2020-07-19T13:27:20Z")
The time course of antibody fading is pretty similar to that of the common cold causing HCoVs according to [the source article](https://www.medrxiv.org/content/10.1101/2020.07.09.20148429v1.full.pdf+html). I’ve bolded a few very important bits. > [@](#): > > **The more transient Ab responses in the lower disease severity cases in our cohorts reflect more the immune response to endemic seasonal coronaviruses** (i.e. those associated with the common cold) > which have also been reported to be more transient.2 For example, a recent report of 10 individuals studied over a 35-year period showed re-infections with endemic coronaviruses > were frequent 12 months after an initial infection.14 Further, individuals experimentally > infected with endemic alphacoronavirus 229E, generated high Ab titres after 2 weeks but these rapidly declined in the following 11 weeks and by 1 year, the mean Ab titres had > reduced further but they were still higher than before the first virus challenge.10 **Subsequent** > **virus challenge lead to reinfection (as determined by virus shedding) yet individuals showed** > **no cold symptoms**.10 > > The nAb titre required for protection from re-infection in humans is not yet understood. … > > … **the role T-cell responses generated through either infection36 or vaccination play in controlling disease cannot be discounted in these studies** and defining further the correlates and longevity of vaccine protection is needed. Taken together, despite the waning nAb titres in individuals, it is possible that nAb titres will still be sufficient to provide protection from COVID-19 disease for a period of time Following the T-cell citation (36) leads to [this article](https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1.full.pdf+html) which I find very important. Bolded for emphasis. > [@](#): > > One sentence summary > **SARS-CoV-2 induces robust memory T cell responses in antibody-seronegative and** > **antibody-seropositive individuals with asymptomatic or mild COVID-19.** … > > … Our collective dataset > shows that SARS-CoV-2 elicits robust memory T cell responses akin to those > observed in the context of successful vaccines, suggesting that natural exposure or > infection may prevent recurrent episodes of severe COVID-19 also in seronegative > individuals. … > > … Individuals in the convalescent phase after > asymptomatic/mild COVID-19 were traced after returning to Sweden from endemic > areas (mostly Northern Italy). These donors exhibited robust memory T cell responses > months after infection, even in the absence of detectable circulating antibodies specific > for SARS-CoV-2, indicating a previously unanticipated degree of population-level > immunity against COVID-19. ---
**Author:** ![Dr\_Paprika](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr_paprika/32/3042_2.png) [@Dr\_Paprika](https://boards.straightdope.com/u/Dr_Paprika)\ **Post date:** [July 20, 2020, 2:18am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/13 "2020-07-20T02:18:43Z")
Thank you for those two articles. Very informative. Kind of scary. ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [July 20, 2020, 3:20am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/14 "2020-07-20T03:20:00Z")
The second very hopeful to my read! Titres rise and titres fall but specific memory T-cell responsiveness is where long-lasting immunity lives. At least as a general rule … ---
**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [July 20, 2020, 11:53am UTC](https://boards.straightdope.com/t/how-does-coronavirus-play-out/915258/15 "2020-07-20T11:53:51Z")
More on the T-cells story, specifically more on T-cell responsiveness without exposure and lasting protections. Antibodies are where the streetlight is, but maybe not where the keys are. > **[Beyond antibodies, the immune response to coronavirus is complicated](https://arstechnica.com/science/2020/07/beyond-antibodies-the-immune-response-to-coronavirus-is-complicated/)** > > T-cell-based immunity may offer longer protection, but initial results are confusing. > [@](#): > > One of the potentially reassuring findings was that people who had been exposed to the original SARS virus 17 years earlier still had T-cells that responded to fragments of the virus. This was true even though the antibody response to this virus had generally faded after several years. Less surprisingly, the people who had recently had COVID-19 also had T-cells that responded to fragments of the virus’s proteins. > > But there was a striking feature of the SARS and COVID-19 fragments that the T-cells responded to: many of them were identical. While SARS-CoV-1 and -2 are distinct viruses with different evolutionary histories, many of their proteins remain extremely similar. (That’s probably because they continue to perform similar functions, and thus there’s evolutionary pressure against changes.) As a result, several of the fragments that were made based on the SARS-CoV-2 proteins happened to be identical in the equivalent protein of SARS-CoV-1. So a T-cell that recognized one of these fragments could recognize both viruses—even though it came from a patient who had been exposed to only one. … Participants who had never been exposed to either SARS virus also had some T-cells that recognized pieces of SARS-CoV-2 proteins. This wasn’t true for every participant in the unexposed group; only about half of them had these reactive T-cells. But again, it was mostly based on cells that reacted to pieces of protein that were identical between SARS-CoV-2 and viruses that cause the common cold. > > Mostly, but not all. There were two exceptions to this—two fragments of protein that didn’t look like the cold virus but provoked a response from T-cells of unexposed participants—and the researchers struggle to explain them. … > > … the fact that this response is only present in a subset of the people who have never been exposed could potentially account for some of the differences in the severity of COVID-19 symptoms. There’s obviously a lot more work to be done here. > > The importance of T-cell-based immunity is also critical to understanding the issue of the apparently highly variable antibody response as well as the indications that it may fade out rapidly once the SARS-CoV-2 infection is cleared. This study indicates that T-cell responses are consistent and strong in this small population. The parallel work on SARS patients indicates that this response also lasts much longer than the antibody-based immune response. So, if it’s sufficient to provide protection from reinfection, then we might be able to worry less about the erratic antibody response. Again, we don’t know yet. > > This could also have implications for the development of vaccines, which tend to focus on the production of neutralizing antibodies. > > All of which implies that there’s an urgent need to better understand the T-cell response to SARS-CoV-2, which is unfortunate, given how challenging studying T-cells is. Challenging to study but very critical to knowing how COVID-19 plays out.