# What does this tell us--so many asymptomatic people test positive? **URL:** \ **Category:** The Quarantine Zone\ **Tags:** covid-quarantine\ **Created:** [May 8, 2020, 4:25pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416 "2020-05-08T16:25:15Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![ThelmaLou](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thelmalou/32/390_2.png) [@ThelmaLou](https://boards.straightdope.com/u/ThelmaLou)\ **Post date:** [May 8, 2020, 4:25pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/1 "2020-05-08T16:25:15Z")
In the [San Antonio Express-News](http://digital.olivesoftware.com/olive/ODN/SanAntonioExpressNews/shared/ShowArticle.aspx?doc=SAEN%2F2020%2F05%2F08&entity=Ar00102&sk=6BF041BB&mode=text) this morning, the following story appeared: > [@](#): > > …On Wednesday, no fewer than 222 of 259 inmates at Bexar County Jail who were positive and presumably contagious did not feel sick. At the Southeast Nursing and Rehabilitation Center, where at least 18 residents have been killed by the virus, 56 of 74 residents who tested positive showed no signs of illness. > > The tests indicate the dangerous and sometimes deadly virus is even more infectious than previously understood, potentially spreading rapidly on the streets from symptom-free carriers as Texas slowly reopens its smothered economy. > … We’ve known this for a while, namely, that lots of people walk around positive for COVID and don’t show symptoms _yet_, or in fact, ever. This makes me wonder if COVID isn’t something like e.coli or staph (I know those are bacteria, not viruses), where they are all over our world and our bodies, but it takes a certain confluence of conditions to make the person show symptoms and get sick. I’m not a biologist and wouldn’t even know how to play one on TV, but maybe someone who knows about this kind of thing will chime in. ARE their ubiquitous \*\*viruses \*\*in our world that may or may not make someone sick at any particular time? I guess the “common cold” falls into this category. COVID is different because it can (but may not necessarily) escalate rapidly into a life-threatening condition-- is that it? The headline of the article quoted above is: “Jail could be microcosm of the city.” Could it be that in a city of 1.4 million, one million people might have the virus but be asymptomatic right now… or permanently? Has this question already been answered somewhere and I’ve just not seen it? I know the question of why some people get sick and others don’t is being explored. My head is spinning from a data overload. Right now, this post strikes me as very naive, but I’m going to leave it, as it’s something I’ve been wondering. ---
**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:** [May 8, 2020, 4:44pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/2 "2020-05-08T16:44:35Z")
> [@ThelmaLou](#): > > The headline of the article quoted above is: “Jail could be microcosm of the city.” Could it be that in a city of 1.4 million, one million people might have the virus but be asymptomatic right now… or permanently? Obviously in jail social distancing is virtually impossible - it’s more like a cruise ship than a “microcosm of the city”. It does give some indication of what _could_ happen in a city without social distancing. In order to estimate the prevalence of the disease, you need to test a random representative sample of the entire population, not just people who are at risk or show symptoms (and obviously not just a few people in one prison). But the lack of test kits has meant that we just haven’t done much random testing, we don’t have good data. But although we don’t know the asymptomatic prevalence exactly, from what we do know it’s not possible that it could be 70% in the general population. If it were that high, we’d see far more vulnerable people sick and dying. ---
**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:** [May 8, 2020, 4:50pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/3 "2020-05-08T16:50:27Z")
Some discussion here: > **[Coronavirus (COVID-19) Overview](https://www.webmd.com/covid/coronavirus)** > > COVID-19 is a new type of coronavirus that causes mild to severe cases. Here’s a quick guide on how to spot symptoms, risk factors, prevent spread of the disease, and find out what to do if you think you have it. ---
**Author:** ![ThelmaLou](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thelmalou/32/390_2.png) [@ThelmaLou](https://boards.straightdope.com/u/ThelmaLou)\ **Post date:** [May 8, 2020, 5:28pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/4 "2020-05-08T17:28:47Z")
> [@Riemann](#): > > Some discussion here: > > [Coronavirus & COVID-19 Overview: Symptoms, Risks, Prevention, Treatment & More](https://www.webmd.com/lung/news/20200424/more-data-bolsters-higher-covid-prevalence) Interesting. From that link: > [@](#): > > … > Also in Boston, at one homeless shelter none of the 146 people who tested positive had any symptoms. Aboard the aircraft carrier USS Theodore Roosevelt, 600 crewmembers have tested positive, but at least 350 of them are asymptomatic. In an Ohio prison that did widespread testing, 73% of inmates—more than 1,800 people—were confirmed to have the virus, many without symptoms. > > A report that relied upon CDC data for people with influenza-like illnesses estimates that at least 8.7 million people were infected with coronavirus during a three-week period in March. And a new analysis of widespread testing in the town of Vo, Italy, found that 43% of people who tested positive showed no symptoms. Neither report has yet been peer reviewed. > … It seems to me that the most important question to be answered is why do some people who have COVID get sick and others do not? Clearly there’s a lot of it around and there’s going to be a lot of it around for a long time. And avoiding “catching” the virus (not a precise term, I know) seems to be next to impossible over the next months or years. But plenty of people who have it do not get sick. Why? ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [May 8, 2020, 5:42pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/5 "2020-05-08T17:42:20Z")
You are asking the questions that the doctors are asking. How infectious is it really? What is the actual percentage of people who get symptoms and the percentage who have none? What is the rate of severe effects vs mild cases? And why does it affect different people differently? I’d the doctors had those answers, we’d be a lot better with regards to prevention without requiring general stay at home orders. And the search for treatments and cures would have solid directions to pursue. ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [May 8, 2020, 5:46pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/6 "2020-05-08T17:46:51Z")
Without follow-up monitoring on asymptomatic individuals, we can’t really say that they never get sick. And we also don’t know how many people keeling over from COVID-19 were asymptomatic individuals. In other words, how many of the unconfirmed COVID deaths are folks who didn’t have the cardinal COVID-19 symptoms that send people to the hospital, but nonetheless had signs and symptoms that we will one day recognize as being associated with COVID-19? There could be a lot of people whose deaths are recorded as being caused of “natural causes” instead of COVID-19 simply because they were never tested for the virus, but their heart attack, stroke, or whatever was indeed caused by the virus. ---
**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:** [May 8, 2020, 5:54pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/7 "2020-05-08T17:54:15Z")
Apparently, the _majority_ of people with [flu](https://www.nhs.uk/news/medical-practice/three-quarters-of-people-with-flu-have-no-symptoms/) are asymptomatic as well, and this is also true of [polio](https://www.cdc.gov/vaccines/pubs/pinkbook/polio.html#features). I had no idea! ---
**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:** [May 8, 2020, 5:57pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/8 "2020-05-08T17:57:03Z")
> [@ThelmaLou](#): > > It seems to me that the most important question to be answered is why do some people who have COVID get sick and others do not? Sure, but I guess I’m puzzled as to why you think this is a novel question, or why that news article in particular raises any issues we haven’t already been obsessively scrutinizing. Isn’t this _the_ major question that everyone has been talking about since this thing began? Most notably, huge apparent differences in fatality rates between different countries? ---
**Author:** ![ThelmaLou](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thelmalou/32/390_2.png) [@ThelmaLou](https://boards.straightdope.com/u/ThelmaLou)\ **Post date:** [May 8, 2020, 6:22pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/9 "2020-05-08T18:22:50Z")
> [@Riemann](#): > > Sure, but I guess I’m puzzled as to why you think this is a novel question, or why that news article in particular raises any issues we haven’t already been obsessively scrutinizing. Isn’t this _the_ major question that everyone has been talking about since this thing began? Most notably, huge apparent differences in fatality rates between different countries? Frankly, I’m puzzled, too. In my OP I said I thought this was a naive question, but I decided to post it anyway. I’m puzzled as to why that puzzles you. 🙂 There are a lot of questions about COVID flying around-- too many. Too many statistics, charts, graphs, color-coded maps. I also said in the OP, “My head is spinning from a data overload.” It’s possible with limited resources (and time is one of those resources) to get lost in too many questions and too much data. One must sort out and focus on what is the most important (as in what will have the most impact) data and the most important questions. For example, we’re seeing a lot of death statistics-- deaths per unit of population. Interesting and very sad, but not THE most important piece of data. I believe THE MOST IMPORTANT question is \*why some people get sick and some people don’t. \*Not why some people who get sick die, or how many of them die, or what percent of the population they represent. Usually they die because of comorbidity. Why do some people get sick and some people don’t? And ultimately, how can we keep asymptomatic (of which there seem to be lots and lots) people from getting seriously ill? ---
**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:** [May 8, 2020, 6:50pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/10 "2020-05-08T18:50:40Z")
First, yes asymptomatic rates as a subject has been discussed here, [in this thread](https://boards.straightdope.com/sdmb/showthread.php?t=893475), but last update was 4/23 so due for a bump … Second to one of your specific questions - yes, there are fairly ubiquitous viruses “that may or may not make someone sick at any particular time”. Yes there has to be some confluence of viral, host, and other factors, that determine when it is just there, and when it cause disease. In that regard I found [this interesting little study](https://erj.ersjournals.com/content/48/suppl_60/PA2602) from 2016. Asymptomatic individuals having bronchoscopies done for other reasons screened during the exam for viruses commonly known to cause disease by exhaled breath and bronchoalveolar lavage (BAL). > [@](#): > > Forty six percent (13 of 28) had a detectable virus in either their exhaled breath (4) or BAL sample (4), or both samples (5) … One patient had 2 viruses detectable concurrently (RV and Influenza B) in both exhaled and BAL samples. > > Conclusion: This preliminary analysis suggests that asymptomatic carriage of viruses may be more common that previously recognised and that respiratory viruses likely contribute to the microbiome of the lung. This one documenting [asymptomatic shedding](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6041500/) using a convenience sample of NYC tourists. > [@](#): > > … A total of 6.2% of samples (168 individuals) tested positive for at least one virus, with 5.6% testing positive in the summer arm and 7.0% testing positive in the winter arm. Of these, 85 (50.6%) were positive for human rhinovirus (HRV), 65 (38.7%) for coronavirus (CoV), and 18 (10.2%) for other viruses (including adenovirus, human metapneumovirus, influenza virus, and parainfluenza virus). Depending on the definition of symptomatic infection, 65% to 97% of infections were classified as asymptomatic. … > > … Though having symptoms is predictive of virus positivity, there are high levels of asymptomatic respiratory virus shedding among the members of an ambulatory population in New York City. … Note as you suspected, rhinoviruses and the common cold causing human coronaviruses led the list. Even for [influenza](https://wwwnc.cdc.gov/eid/article/22/6/15-1080_article) - > [@](#): > > … The prevalence of asymptomatic carriage (total absence of symptoms) ranged from 5.2% to 35.5% and subclinical cases (illness that did not meet the criteria for acute respiratory or influenza-like illness) from 25.4% to 61.8%. … COVID-19 is not so different in this feature. In some people at some times based on some confluence of factors it can cause serious disease inclusive of death, and in some … nothing. It is different mainly in how many have no prior exposure to it (even if recent and/or frequent exposure to its close relatives impacts how one responds to it), in how many are being exposed in a fairly short time period, and (whatever the actual infection fatality rate turns out to be) in that its infection fatality rate (IFR) seems to be higher than seasonal influenza, let alone those other ubiquitous viruses. Your questions are not at all naive. The true rate of infections, inclusive of asymptomatic and very mild cases, would give researchers the real denominator to know IFR. And, coupled with a better harder understanding of how contagious those individuals might be, guide policy recommendations. ---
**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:** [May 8, 2020, 7:00pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/11 "2020-05-08T19:00:53Z")
> [@ThelmaLou](#): > > … THE MOST IMPORTANT question is \*why some people get sick and some people don’t. … Lots of speculations out there about it, but data and evidence? Other than lack of risk factors? Lacking. I’ve stated this in previous threads but my belief is that understanding why _children in particular_ are at such relatively low risk of getting sick (not just an order of magnitude less risk than adults, but also than children are at risk from getting sick with influenza) is a key mystery to give clues to the answer more broadly. Maybe variations in where different receptors are expressed and in what relative numbers, maybe frequent and recent exposures to the common cold causing coronaviruses that allow them to trigger off a better cellular immune reaction and create a large population of then specific memory T-cells, maybe … it is not too difficult to come up with a list of hypotheses (the second is my preferred), but getting the evidence to support one or the other? May be a while. ---
**Author:** ![ThelmaLou](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thelmalou/32/390_2.png) [@ThelmaLou](https://boards.straightdope.com/u/ThelmaLou)\ **Post date:** [May 8, 2020, 7:04pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/12 "2020-05-08T19:04:13Z")
> [@DSeid](#): > > …Your questions are not at all naive… Thank you. We can always count on you for sensible and informative posts. I might be in love with you. I’m a pushover for well-informed, grammatically correct guys. > [@](#): > > …The true rate of infections, inclusive of asymptomatic and very mild cases, would give researchers the real denominator to know IFR. And, coupled with a better harder understanding of how contagious those individuals might be, guide policy recommendations. This is EXACTLY what I’m thinking. 🙂 ---
**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:** [May 8, 2020, 7:07pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/13 "2020-05-08T19:07:57Z")
> [@ThelmaLou](#): > > I believe THE MOST IMPORTANT question is \*why some people get sick and some people don’t. \* That being so, your thread title and OP are a bit confusing. You ask why so many asymptomatic people test positive (based on an article describing a prison population), when the question you now say you’re concerned with is why so many people who test positive are asymptomatic. These are really quite different questions. The former question is about how far the disease may have spread in the population without our knowledge; the latter question is about risk factors for morbidity and mortality. Prior recent thread discussing the latter issue: [http://boards.straightdope.com/sdmb/showthread.php?t=894647&highlight=adaptive](http://boards.straightdope.com/sdmb/showthread.php?t=894647&highlight=adaptive) If there are different strains of the virus affecting different populations, that’s obviously critical to understand, as are environmental factors and behavioral factors that we can change. But as for individual risk factors - there’s a lot of natural variation in our immune systems, some of it effectively random - antibody and immune receptor diversity is generated randomly. To the extent that genetics is a risk factor, it may or may not be important to dedicate resources to understand it quickly. Even if we get good data, there may be no practical assay to test the population in large numbers for the genetic risk factors; and there may not be much that at-risk people can do to that they should not be doing anyway. So I’m not sure I think that understanding innate risk factors is necessarily the most urgent priority. With finite resources, I’d say developing more effective treatment protocols and developing a vaccine have greater certainty to yield results that save a lot of lives. ---
**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:** [May 8, 2020, 8:58pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/14 "2020-05-08T20:58:19Z")
**Reimann** to some degree the question of why some groups in particular DO get sick and why some groups in particular DO NOT are different approaches to the same problem, but ones that inspire different approaches to it. Looking for something else I found [this](https://news.harvard.edu/gazette/story/2020/04/a-way-to-manage-surge-in-nursing-home-covid-19-cases/) by the way, from a month ago so numbers old, but still the discussion relevant to this thread - > [@](#): > > Michael Mina, an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health and its Center for Communicable Disease Dynamics, said Friday that he believes the coronavirus that causes COVID-19 is more transmissible than previously thought … A virus that has already spread widely in the population requires a different response than one whose spread involves the cases already found through current testing, Mina said. If the virus has already infected many more people than testing to date has shown, that would mean that the very serious cases in hospitals today are a small portion of the total number, and that pouring resources into contact tracing might not be the best policy. If millions of people have already been infected and recovered, that would mean that the population is on the path to herd immunity — the threshold at which the level of immunity in a population naturally inhibits further transmission. > > On the other hand, he said, if the current testing has captured somewhere close to the true number of cases, that would mean the virus is more virulent, with a significant proportion of cases becoming serious. It also means that efforts to suppress the virus through contact tracing are important. ---
**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:** [May 8, 2020, 10:10pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/15 "2020-05-08T22:10:11Z")
> [@DSeid](#): > > **Reimann** to some degree the question of why some groups in particular DO get sick and why some groups in particular DO NOT are different approaches to the same problem, but ones that inspire different approaches to it. That wasn’t the distinction I was drawing. ---
**Author:** ![excavating\_for\_a\_mind](https://avatars.discourse-cdn.com/v4/letter/e/e8c25b/32.png) [@excavating\_for\_a\_mind](https://boards.straightdope.com/u/excavating_for_a_mind)\ **Post date:** [May 8, 2020, 10:13pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/16 "2020-05-08T22:13:30Z")
If only there was a way to map the genetic genomes of people who succumbed to CoViD-19 that we could compare to people who appear not to become ill. This might give us an indication on which individuals are most susceptible based on their DNA. But, wait. We do have that information. Companies like 23 and me, [Ancestry.com](http://Ancestry.com), and others have assembled enormous databases of human genomes, and it is all but certain that many of those who have died, as well as those who are asymptomatic, are represented in those databases. Of course, those companies have [del]spent[/del] made millions of dollars assembling those databases and probably wouldn’t be interested in contributing that information to science to help humankind find a solution, so it’s probably not reasonable to expect them to share any of their proprietary information. ---
**Author:** ![susan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/susan/32/17537_2.png) [@susan](https://boards.straightdope.com/u/susan)\ **Post date:** [May 8, 2020, 11:12pm UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/17 "2020-05-08T23:12:24Z")
They publish articles about their findings pretty frequently, and provide alerts for people with genetic factors that they have researched. ---
**Author:** ![thorny\_locust](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thorny_locust/32/431_2.png) [@thorny\_locust](https://boards.straightdope.com/u/thorny_locust)\ **Post date:** [May 9, 2020, 12:05am UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/18 "2020-05-09T00:05:29Z")
Has anyone seen any figures for what percentage of high-risk people who test positive are symptomatic? I’ve seen lots of figures for what percentage of people who are significantly ill with covid-19 are in the categories understood to be high-risk. But does that mean that nearly everyone who’s high risk and catches it gets significantly ill, or are there a lot of high-risk people who appear to be asymptomatic and/or have very mild symptoms? ---
**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:** [May 9, 2020, 1:06am UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/19 "2020-05-09T01:06:28Z")
Quite a few not symptomatic, at least at time of testing. [For example.](https://www.njtvonline.org/news/video/asymptomatic-long-term-care-staff-helped-spread-covid-19/) > [@](#): > > Deputy Health Commissioner Marcela Maziarz said all 3,700 staff and residents at the 16 facilities included in the program were tested for the virus, and significant numbers have turned out to be positive even though they didn’t show symptoms of the disease. … > > …the nasal swab tests showed that, out of 20,69 residents, 16% tested positive, as did 9% of 1,719 health care staffers. … “For some facilities, we found as high as 61% — both of staff and residents — with COVID-positive tests,” Maziarz said. “These were asymptomatic individuals, so many did not show symptoms, but now are showing back positive on the test.” [This too.](https://www.mcknights.com/news/hcr-manorcare-70-percent-of-covid-19-infected-employees-asymptomatic/) > [@](#): > > Seventy percent of employees and up to half of patients found to be COVID-19 infected by nursing home giant HCR ManorCare were asymptomatic at the time, says the chain’s medical director. > > The novel coronavirus is “the silent killer which we’ve learned so much about but still have so much to learn,” said HCR ManorCare Medical Director Mark Gloth, M.D., on a conference call with the media Tuesday. “It is virtually impossible for us to keep it out of our facilities. In fact, we know it’s highly likely we’ll see it in our centers” when it’s already seen in the surrounding community. Unclear what if any fraction of the residents who were asymptomatic at time of testing became symptomatic over the next several days. [In this most of the those called asymptomatic did go on to symptoms …](https://www.physiciansweekly.com/covid-19-asymptomatic-transmission-fueled-nursing-home-death-toll/) But still some not. > [@](#): > > Of the 76 residents of the nursing home who participated in point-prevalence surveys, 48 (63%) tested positive; of the 48 who tested positive, 27 (56%) were asymptomatic at the time of testing. > > Twenty-four subsequently developed symptoms, with the median time to symptom onset of 4 days. ---
**Author:** ![jackdavinci](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackdavinci/32/3259_2.png) [@jackdavinci](https://boards.straightdope.com/u/jackdavinci)\ **Post date:** [May 9, 2020, 1:18am UTC](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416/20 "2020-05-09T01:18:46Z")
Is there a way to tell both whether someone has been exposed, and also whether they are currently contagious and/or immune? [Next page](https://boards.straightdope.com/t/what-does-this-tell-us-so-many-asymptomatic-people-test-positive/853416.md?page=2)