I don’t intend to fill this site with information or bad news about coronavirus, as you can get that most everywhere, including the New York Times, and most of the detailed stuff is above my pay grade. But I thought the information below was well worth passing along.
Are you tired of hearing the advice to wash your hands and keep social distance, given that you’ve already heard it a gazillion times on Facebook and we already know what to do? Then it’s time to educate yourself further. My primary care physician, Dr. Alex Lickerman, is the best doctor I’ve ever met, and I’ve known many. He’s not only extremely knowledgeable (he’s young but was head of primary care at the University of Chicago Hospital for seven years, leaving because he didn’t like the strictures of rapid patient turnover), but reads the scientific literature thoroughly and bases his advice on both that and his own experience. He also posts on his two-doctor practice’s website (he calls it a “blog”), ImagineMD, and has been putting up his thoughts and recommendations about Covid-19, updating them as new information becomes available. (You can sign up for a free email subscription.)
The post below, which just came out, is the sixth update in a Covid-19 series that started in February (links to the first five are at the bottom of this post).
Now I know that not everyone will be on board with any doctor’s take (it seems that everyone is an expert on coronavirus!), but do read it and take what you want from it (click on screenshot). I asked Alex if he’d be willing to answer readers’ questions, and he said “Yes. My aim is to stamp out misinformation and spread correct information wherever possible. I’ll answer as I have time.”
So I can’t guarantee that all readers’ questions will be answered or addressed, but if you want to know something, by all means put your query in the comments. But first read the article (click on the screenshot).
Topics covered in the post above include:
- What are the symptoms and typical course of the disease?
- How does testing for the virus work and how reliable is it?
- How is the virus transmitted?
- Should you wear a mask in public?
- Can pets carry coronavirus?
- How do you deal with “coronachondria”—the extreme anxiety associated with people experiencing this pandemic?
- How do you deal with the possibility of gaining weight now that our normal activities, and much of our exercise, has been curtailed?
- How long is this pandemic going to last?
After you read it, feel free to leave questions on these topics and others related to coronavirus in the comments.
Finally, the video below is proffered by Professor Ceiling Cat (Emeritus): Masks may soon be required or recommended for anyone going out in public, at least if you’re to meet other people. I found this video on how to make a dust mask, and given that it’s not easy for non-doctors or non-scientists to buy “regular” masks, this one looks acceptable, and has the advantage of being washable and therefore reusable. I offer this, again, for what it’s worth: I’m not a doctor or epidemiologist. It’s surely not great protection from inhaling aerosolized virus, but will keep you from touching your face (except for your eyes), and it should be a good reminder, when worn, not to do so.
Cool, thanks.
Question for Dr. Lickerman (or anyone else with expertise to answer it):
If one actually gets sick from the virus, to whatever degree of actual illness, how should you take care of yourself, assuming charging off to the emergency room is a bad idea?
Is it the standard advice usually given for caring for flu, or is the care different?
Care is supportive at this point. That means: Tylenol or ibuprofen for body aches/chills/fevers (no study has shown that ibuprofen worsens COVID-19), cough suppressants for the cough, especially if it keeps you awake at night (the only one worth trying in my view is robitussin AC, which contains codeine, and which is prescription only). You should only think about going to the ER if you become short of breath (and not from anxiety, which can be hard to differentiate).
Thank you so much.
Thanks for this. I particularly like the likelihood of survival chart. I presume that is if you catch Corona? I guess there will a be a percentage of folk who never catch it, so one’s chances overall increase a bit! (However, I’m reliably informed that humans still have a 100% death rate long term)
re pets, the Guardian reported that cats may be susceptible to the virus – https://www.theguardian.com/world/2020/apr/01/cats-can-infect-each-other-with-coronavirus-chinese-study-finds – was this reported on this website?
I wonder if that will catch on.
I was going to ask about the viral load theory but it was already addressed in the article. Thanks!
Statistically the chance of death seem to go up a lot when you hit 70 years old. Is there any simple explanation for this in the human biology of aging? Noting also that the 1918 flu was particularly rough on a younger population.
Many theories but nothing proven.
I can shed a bit of of light on this from a general perspective.
As humans age, their immune system generally becomes less reactive: the term for this is immuno-senescence. People become less able to deal with invading pathogens and more prone to developing complications and secondary infections.
It’s a pattern that erupts frequently in many infections and syndromes.
Source: I am a researcher in the field of sepsis and my training is in microbiology and immunology. Currently I’m involved in a project immune phenotyping COVID-19 patients in the St. Louis area. Sepsis and COVID-19 would not typically be thought to be extremely similar but there appears to be an immune paralysis present in severe COVID patients that is very similar to what’s observed in septic patients and we’re examining whether the similarities are superficial or if cellular mechanisms are shared.
Thanks for the information. Very interesting. The opposite that occurred with the 1918 flu may be more rare I would guess. One thought I had heard on this was there may have been an earlier flu that many of the older people were exposed to and this gave some protection against the 1918 flu. The younger people had no exposure to this earlier version and were therefore, hit much harder.
As to that it’s a bit more shakey ground and conjecture.
It’s possible, as you said, that older people had better protection from a previous exposure. It’s also possible, overall probably less likely, that the immune response triggered by the virus in young healthy people was so strong that it was immune mediated damage that contributed to killing those people.
Thanks for the info Drew!
You sound like the right person for this question:
Many of us are of course looking at the stats and wondering “what’s my chance of survival?”
So in my case, being 56, it’s a bit alarming to see how the mortality rate jumps up to 1.3 percent after age 50 up to age 60!
But I’m left wondering how this breaks down further. There’s a lot of talk about general health and comorbidity factors being involved in the outcome – so your risk of dying rises with comorbidities like diabetes, heart problems etc.
This gets me wondering about individual cases like myself. Again, I’m 56, but have maintained a healthy 22 BMI through good diet and exercise, good lung capacity, don’t get sick often, no comorbidity that I’m aware of, all recent medical test markers show good health.
Now, IF part of the reason the mortality rate jumps above age 50 is due to the fact more people tend to start having additional health issues, comorbidities etc, and so this raises the demographic’s overall mortality rage…THEN I could perhaps find some silver lining. Maybe being in good health knocks my chance of dying from COVID 19 a bit down from 1.3 percent.
On the other hand, IF the higher mortality rate once you reach 50 is due to some other aspect that accrues “merely from being older, whatever your health status,” then I’m still stuck in the 1.3 percent for dying.
Your post seems to suggest it is something of the latter – that merely being 56 has significant consequences for my immune system, so I don’t get the healthy benefit effect.
Or…perhaps…it meets somewhere in between:
The risk is up due to an aged immune system, but the risk is brought a little down due to being healthy. So…maybe…being healthy still knocks the risk of dying a tiny bit down from 1.3 percent.
Your thoughts? Thanks!
I think the answer is we don’t know. The jump in mortality in ages 50-59 could be exactly as you conjecture, that a lot of people that age have co-morbidities. Or it could be that simply being that age is the risk (unfortunately, looking at the statistical analyses in multiple papers, the latter is what seems to be more likely). But again look at it this way: if you get COVID-19, you have a 98.7% chance of surviving it!
Thanks Alex! (And excellent blog too!)
I have a friend my age in London England with COVID symptoms. It sounds brutal and relentless over the past two weeks or so! Every time he starts to feel better it seems to come back harder.
The experience of his family seems to follow the broad trends: It seems to have hit him harder than his wife – she seems to be recovered. And their 12 year old is strolling through the whole thing seemingly impervious (asymptomatic, at least).
Alex is spot on.
With sepsis, at least, mortality increases in patients over 65 with a significant correlation to mortality as age continues to increase past that, however sepsis and COVID are two different beasts.
Immune dysfunction could be a factor in people 50 and above in COVID, or it could be co-morbidities. My own gut feeling, based on my experience would suggest it more likely to be co-morbidities, but Alex thinks it’s more likely to be age related. I haven’t performed an in depth examination of co-morbidiety tables in the COVID papers that have come out, and I’m sure Alex has. If he thinks that it appears more likely to be an age based factor rather than co-morbidities I’ll defer to his expertise and down-grade the importance of my gut feeling.
Clarification, when I said “people 50 and above in COVID”, I meant “people 50-59 in COVID” since that was the age range most relevant to your comment and Alex’s reply.
Thanks for chiming in drew. I appreciate it!
I’m wondering how to think about a second wave of the virus if that comes (e.g. if it wanes in the summer, hits hard again in the fall).
On one hand I can imagine we’d be in a better place to handle it – having the world mobilized, used to doing what is necessary and fast to cut transmission, and hopefully manufacturing of medical equipment/masks ramped up so we aren’t starting with a shortage.
On the other hand, perhaps we will have been so decimated and diminished by the first waves we end up in a weakened position to fight the second wave. (In the first wave we started with everyone employed, healthy, many with money. By the time the second wave hits, many will be in far more desperate circumstances).
What I’d add (prior to reading this post further) is the idea of risk. It will be difficult to achieve zero % risk. So, by taking these precautions, we decrease risk.
In particular, with the intense concern about “masks”, I do not see how placing an object directly in front of the nose or face cannot decrease risk of transmission – that masks do not work (as we’ve heard elsewhere). Consider the firm guidance – for those with a bug – to cover the mouth, preferably with the inside of the elbow. If that works, then covering the mouth works – there should be nothing special about the elbow.
The mask thing also supports the idea to control the breathing to reduce risk : especially in a risky scenario. Someone sneezes nearby, it’s dusty, etc. – holding the breath, and exhaling, might help blow the infective particles away.
And then there’s how these things are used. Improper use and all bets are off.
I really don’t know, but I have two guesses as to why they didn’t initially recommend masks for asymptomatic people.
1. They didn’t want people thinking wearing a mask would let them go out in public. I.e., they didn’t want the decrease in risk from wearing one to lead to a net increase in risk from going out more often because you’re wearing one and thus perceive yourself to be safe.
2. If the vector “touching your face” is more important than direct inhalation, wearing a mask might only provide a marginal decrease in risk.
In any event, the government line seems to have changed to ‘yes, mask up.’
Ah, big edit: it appears your question was addressed in the article, ThyroidPlanet. The summary is basically that masks that don’t have an airtight seal just aren’t very effective at stopping an incidental intake of viral particles. Though AIUI they do reduce the amount of aerosolized viral particles an infected person breathes out.
Given that asymptomatic people can spread the virus, it seems reasonable now to mask up when we’re going out. Using the assumption “I don’t know whether I’m uninfected or merely asymptomatic”.
To be fair, you forgot one;
3. There was no evidence it would help. Though it seems likely that any respiratory virus could be transmitted through the air, it appeared (and it still does) that the main route of transmission is through direct contact. So social distancing was the method of choice to reduce transmission through the air.
I saw a video (I’ll try to find it) that showed that unless the mask fits securely to your face, when you breathe most of the air moves through the gaps, not through the mask.
Even an ill fitting mask should stop much of the large droplets one expels when coughing though. So I should think that non-symptomatic people wearing them might have an effect on transmission. The article says that effect would be modest and I agree. Social distancing is much more effective, though.
Simple masks (ag surgical masks and home made masks reduce the cloud of micro-droplets when you talk or cough, which has 2 results:
– you reduce the chances of infecting somebody directly, by them inhaling your aerosol (or getting it into their eyes)
– you reduce the surrounding surfaces being sprayed with the virus.
I’m confident if everybody would wear a simple mask in public, the R0 would be significantly reduced.
Note, I do not advocate this as a replacement for hand hygiene and social distancing, just as a probably useful addition.
Moreover, it could be argued that cashiers, just like health care givers, should be provided with N95 masks, that give some personal protection.
Thank you, Jerry and Dr. Lickerman. I will check out the blog as one source of information for a brief online lecture about the virus. I can tell you that the statements here comport very well with what I had read about it elsewhere.
I do have a question.
What is the evidence that the host which transmitted the virus to humans was pangolins?
Mark – it seems the link to pangolins was a mistake and the result of an “embarrassing miscommunication”. As of a few days ago, the animal source was not known (bats are suspected)
https://www.nature.com/articles/d41586-020-00548-w
I think the only evidence is the market for pangolin meat etc. :
Laura Kahn – Bats, Cats and Coronaviruses: What You Need to Know About C…
Laura H. Kahn, M.D., M.P.H., M.P.P.
Princeton University : https://youtu.be/HR3mE5p3jLU
… I’d have to read about it though.
Thanks to both of you!
sub
sub sub
Also recommend the “this week in virology” (twiv) podcast which is hosted by a senior virologist at columbia and usually presents a mix of phd’s, md’s, and mph’s with a bent toward research but also significant clinical presence. They accept email questions and usually spend half of the podcast reading and answeing listener email. Url is
http://www.microbe.tv/twiv/
Looking forward to your docs website
“But I thought the information below was well worth passing along.”
Definitely, thank you.
“If you have symptoms consistent with COVID-19 and test negative, you might still be infected.”
Only 75% accuracy? That is worrisome, have not seen that reported in the media.
It’s important to realize that 75% is the negative predictive value. This means if the test says you’re negative, there’s still a 25% chance or so that you’re actually positive. If you have no symptoms whatsoever, it’s probably a true negative. If you have symptoms consistent with COVID-19, you’re probably in that 25% or so of false negatives. The positive predictive value of the test is 97%, meaning that if your test is positive, there’s only a 3% chance it’s wrong.
My neighbor (junior doctor) test came back negative on Tuesday, and he is back at work today!
Meanwhile, the subject of the test has continued to proceed to navigate the days, risks and everything – what does the original test say at that point?
Sorry, @ThyroidPlanet, I don’t understand your question. Or was it even directed at me?
Oh, ahhh – It’s a rhetorical question (for my own amusement really, didn’t expect an answer).. to illustrate that a test is meaningful given the conditions, but also has a timeframe- so e.g. if an individual gets a test done and then goes to an amusement park, the first test obviously only says something about the individual up to the testing time. So then a few days later, when all the data comes in, the plot reflects that test. But that tells us nothing about what that individual is doing “now”.
I thought it’s just an interesting detail to consider when evaluating all these plots.
Even more interesting is that viral replication in mild cases seems to fall off after day #5 of infection, so the likelihood of a positive PCR test probably drops off depending on the timing of the testing in the course of an individual’s infection. This may account for the high false negative rate.
Thanks for that. I’m not a nervous Nellie by nature, but even I found Dr. Likerman’s straightforward information and tranquil tone reassuring.
I also appreciate the Good Doctor’s reminder about diet and exercise. I generally workout regularly, but I’m given to periodic bouts of physical sloth, and I can feel the lassitude setting in with this shelter-in-place stuff. I’m trying to make a point of taking semi-diurnal constitutionals of a couple miles a pop, and I’ve got a pair of dumbells (no, not my sons; this time I’m talking about the handweights 🙂 ) to maintain a modicum of muscle tone.
Stay healthy, one and all.
Of interest:
https://www.virology.ws/2020/04/02/why-is-covid-19-less-severe-in-children/
Thanks for confirming what I thought re. the basis of the test, that it’s RT PCR.
I have friends who keep shouting EVERYONE MUST BE TESTED. I try to patiently point out that that means testing 330M people, and if they come up negative, what do you do tomorrow? Also, running RT PCR is not particularly quick, the amount of equipment needed to run the test is limited, and I suspect that the average clinical lab tech may not be competent to run RT PCR either.
So the question is, do you have any sense of how many RT PCR reactions could be run per day in a major medical hub like Chicago?
A 384 well plate on a typical research lab machine takes a couple of hours to run. So I guess 12 x 384 per machine per day. Most labs have a machine. There are many labs, those dedicated to this sort of thing have many machines and probably much better throughput. So, you could run many thousands perhaps millions of PCR reactions a day in a place with as many medical centers as Chicago. Of course you’d need technicians and reagents. The ability to run tests isn’t an issue, the availability of clinically approved tests, associated reagents and clinically-appropriate labs and clinically certified techs is more of a problem. Even in a medical center most of the machines are used for research, not for clinical assays that return data to patients for medical decisions. Some of the obstacles with clinical testing are legal and administrative. I could have a tech run a qPCR in my lab and publish the data in a paper, but I can’t tell you the result for clinical purposes unless I want a conversation with a lawyer, and an exit interview with HR.
As you note, PCR testing only gives you data on an active infection, it doesn’t tell us if you had it last month. We still need serological testing to see who has been exposed. Once we have those data we can separate vulnerable from putatively immune populations. Those tests are only just coming online and how long it will take to screen a good portion of the population is unclear (at least to me)
Thx!!
I’m always struck by the large number of tests performed compared to the relatively miniscule number of tests that result positive. I’m curious as to how many of those tested have symptoms and how much is just panic-driven. Also, if you’re not going to do anything different from what you’re already doing if you test positive, then what’s the point of getting tested? Seems like a waste of valuable resources. Am I missing something?
I have no medical expertise but I would guess testing is essential to monitoring the prevalence and spread of the disease. It also gives us evidence about the efficiency of mitigation efforts and, once the first wave has passed, will be a key tool in relaxing distancing.
Yes but. Bear in mind the biases introduced. If you test only patients in whom you want to confirm disease (those presenting with symptoms consistent with the disease then you get ballpark 20% positive – varies with location and criteria). You are clearly not testing asymptomatic, or likely mildly symptomatic patients so they don’t get counted.
To monitor prevalence you need to randomly test people. Icelandic data suggests lots – perhaps 50% of positive tests not associated with symptoms. And, that also misses the asymptomatic patients who have got through the disease and no longer harbor virus. Hence a need for serologic tests which ask whether you have been exposed to the virus in the past.
“I would guess testing is essential to monitoring the prevalence and spread of the disease.”
This may well be true, but it doesn’t address my question, which is why so many people bother to get tested in the first place. Few people, I would guess, say “I’m going to go get tested because researchers need the data for monitoring prevalence, etc.”
I suspect there is a lot of people who are lining up for testing are being driven by panic and not symptoms or having been in contact with someone who has the virus. What I fear is that people get tested, it comes back negative, and they think they don’t have to take the same precautions.
Since you touch on an eventual vaccine, and since the U of Pittsburgh just yesterday announced a candidate vaccine involving the spike protein and about to enter Phase I trials, this might be a good place for this lecture by Columbia Professor Racinello on antiviral vaccines. It starts with historical things that most of us here probably know, and then gets into different approaches.
One of the difficulties with influenza vaccines as many of us know is that the targeted proteins are rapidly changing, and so new ones need to be devised yearly. (And altho he doesn’t comment on it, why they change rapidly illustrates a principle of protein evolution.) Near the end around 51:00 is a strategy for devising vaccines to the less-imunogenic parts of the target protein that are more constant.
If an approach like this is taken against the current pandemic, we could eventually wind up with a vaccine series against the whole SARS class of coronaviruses.
I would like to learn more about how rapidly COVID 19 evolves, as this effects the prospects of having a vaccine and the prospects of having a long term vaccine. I understand it does evolve at a pretty good clip, fast enough to jump hosts and to change also while spreading in humans. But is it so fast that a vaccine is going to be especially challenging? I would consider it somewhat good news even if its pace is as such that an annual vaccine might pretty much do it. Like vaccines against the flu virus. But for this one that would be one vaccine i would not skip from time to time!
Of course the rate of evolution itself can change. If it starts evolving like the cold virus then non-existent god help us.
https://hub.jhu.edu/2020/03/30/covid-19-gene-sequencing/
Another good site; http://www.nextstrain.org
Excellent!
To give you an idea of the rate at which it is diverging relative to other viral pathogens, it looks like the COVID-19 causing virus is mutating at a rate somewhat less than the flu but considerably faster than measles.
At the site I linked to below, they have found that the mutation rate for SARS-CoV2 is a little over 23 substitutions/genome/year while for flu they found the rate to be about 47 substitutions/genome/year (reported as 3.5^e-3 subs/site/year) and for the measles about 9 substitutions/genome/year (reported as 5.7^e-4 subs/site/year).
So this virus diverges at a rate slower than the flu, but still pretty high suggesting that any vaccines developed will have to be modified from outbreak to outbreak (or year to year)
I think one key to the evolution is whether it dies out at some point (on a given hemisphere?) for whatever reason. That seems to have been the case with the original SARS and I think to some extent with MERS. If it dies back to a small founder spot (relatvely on the Equator?), then the clock should reset annually. If not, then we keep rolling on until everyone has been exposed / has had a chance to become infected. (Are some of us innately refractive to this one for some reason?). If it goes back to some refuge, then maybe (as with influenza?) the mutability will result in a strain with enhanced infectivity but lower pathogenicity.
In any event, the trick explained in that lecture of coaxing an immune response to the less immunogenic part of the target protein, by first immunizing with the native (in this case) spike protein, so you get an abundant response to the variable region and a lower response to the constant region, and then following with vaccination with the constant region fused to a poorly immunogenic protein in place of the variable region, would be a way of getting around the whole problem. An intriguing and elegantly simple approach!
Congratulations to having found such a sensible primary care physician! This blog post is well written, solely based on facts that are consistent with what I already know. Dr Lickerman presents both what is known and what is not known. He gives well balanced advice. Please send him my regards as a fellow primary care physician.
Here’s a data site for those who have already checked out our world in data, Johns Hopkins, and their local health authorities(well, that’s how I feel about it ) :
https://covid19.healthdata.org/projections
… this is a site which is discussed on a recent blancolirio YouTube video. It has details like number of beds, icu, …
This site is nifty – user can select the state and see a number of key projections like how many beds, how many cases, and which day the peak is expected, given the assumptions like stay at home orders, etc.
Also it’s University of Washington
Dr. Lickerman I’ve read about drugs like
hydroxychloroquine and Plaquenil as possible aids in treatment. Is it likely they are using it to treat patients now, or is it something being tested but not used on all patients.
I address the hydroxychloroquine issue in an earlier post in the series (https://imaginemd.net/blog/coronavirus-march-2020-part-4/), which I’d encourage everyone to read because there’s been so much misinformation about it. The bottom line is it’s nowhere near ready for prime time.
Just for completeness – there is a clinical trial sponsored by the WHO which on going now called “SOLIDARITY”. It is a double blind placebo controlled study to test hydroxychloroquine and three other drugs (also in combination) for treatment of infection with SARS-CoV2. There are (by my count) five other clinical trials going on now as well on it and other drugs.
Good to know. Thanks.
I have a question.
We see charts of fatality rates based on age, but not based on underlying health issues. Is there any data as to fatality rates for various conditions and age, such as, diabetes, asthma, COPD, etc. For example, what about someone in their 70s with asthma?
Yes, that data is beginning to emerge. Hypertension, cardiovascular disease, emphysema, kidney failure, and diabetes seem to be the big ones.
I’m wondering what is keeping this covid-19, as a zoonotic virus from “going back” from humans and infect, say, mammalian livestock.
On the subject of cloth masks. The advice that we have received is that there are data suggesting that cloth masks increase the risk of catching influenza viruses as compared to no mask. No data available on corona virus infections so it’s extrapolation. I don’t know the study to cite but the advice we have been receiving is not to use cloth masks in a hospital setting. That does not address whether they reduce spread in a public setting, which might seem to be a reasonable expectation.
I haven’t seen data on cloth masks per se for influenza, but studies of transmission of influenza specifically among household contacts suggest there may be a modest benefit from wearing surgical masks. Unfortunately, people aren’t very compliant with them in the studies so it’s hard to know if the benefit would be higher if people used them correctly 100% of the time.
The figurative image of the medical mask wear lines on the face makes a clear, strong point.
SUBSCRIBED
This paper just hit my twitter feed from several directions – but it’s surgical not cloth masks. Have not read but for anyone interested
https://www.nature.com/articles/s41591-020-0843-2.pdf
Abstract: We identified seasonal human coronaviruses, influenza viruses and rhinoviruses in exhaled breath and coughs of chil- dren and adults with acute respiratory illness. Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respi- ratory droplets. Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influ- enza viruses from symptomatic individuals.
Well that link didn’t work.
https://tinyurl.com/umxxd3q
Dr. Ilyas Colombowala has co-developed a 3D printed mask; his twitter page has photos, most of the mask is solid plastic which can be sterilized but at the nose there is a changeable square of filter material. “Passed N95 equivalent fit-test with Bitrex (surgical wrap as filter, readily available). Wearable all day. Mask can be resterilized/reused. Nylon-12. Thanks to
@Intermountain3D for co-development”
Other doctors have made whole masks out of the surgical wrap material; Halyard H600 2-ply spun polypropylene. This idea is shown in article ” Second Life: Sterile Wrap Fashioned into Masks ” written by Keren Sookne on healthcarepackaging website
Jerry, What does he think about protecting yourself from contaminated plastic tile floors while shopping. All those droplets produced by breathing coughing, sneezing and talking drift slowly down to the floor where they accumulate for at least one day. To me, it seems pretty clear that you are tracking virus to you car and back home if you don’t use protection. I use disposable shoe covers along with other physical barriers while shopping.
I’m not as concerned about virus on the floor. Unless you’re down on the floor with your hands or touching the bottoms of your shoes with your hands after walking on virus contaminated flooring, you’re not likely to pick it up from that.
Thanks!
On a Sam Harris podcast on the virus, the virologist said that the severity of disease is related to the initial dose. A large dose of viral particles multiplies and outruns your ability for developing a good immune response.
1) What sort of viral dose is typically found on contaminated surfaces per cm squared?
2) How many virus particles does it typically take to get badly ill?
Not proven that the inoculum (initial concentration, or dose, of SARS-CoV-2) relates to disease severity. True in mice for influenza and chimpanzees for hepatitis B, but a quick literature search didn’t come up with anything in humans for me (this isn’t my area of speciality though and I may have missed some papers). But even if true, we don’t yet know the answers to either of the excellent questions you ask.
Thanks
I’ll be making some cloth masks like that one in the video. When I have time, I’ll sew up some too. For those who think they can’t sew, here’s a no-sew method using a bandana, hair ties and coffee filters!
http://www.youtube.com/watch?v=dnBqwowZi5w
From imaginemd.net:
I’m glad we aren’t supposed to wear masks here!
“The Public Health Authority does not recommend the use of mouthguards. There is no scientific evidence that the loosely fitting disposable covers limit infection. They can even lead to increased spread.
– Viruses can accumulate in the mouthguard, and when you take off and on the protection the virus can be transmitted to the hands and thus spread further. It is important to be able to handle the oral protection properly, says the infection protection expert Anders Tegnell at the Public Health Authority.”
[ https://www.svt.se/nyheter/inrikes/forsaljning-av-munskydd-okar-ger-inget-skydd-mot-virussmitta ; my bold]
Obviously you should follow the recommendations of your local health authority/government.
Was just in my workshop and my old stock Harbor Fright brand mask 61434 has this printed on it :
“NIOSH N95”
^^^
This is a mask that is associated with sanding, woodwork, etc. Harbor Fright also extremely cautious to print a booklet to warn essentially that the mask is not guaranteed to prevent any problems, and has to be worn properly or all bets are off.
My point is that “N95” is not just associated with the masks we have been seeing. Personally, I’m starting to equate “N95” with only medical professionals like the doctor in the Google video thumbnail with lines on her face, if anyone knows that one. Perhaps it is misleading. I don’t know. It’s just facts, is what I’m saying – “N95” is on the mask advertised for woodworking.
Oooof – fixed width font needed – ^^^ supposed to be under the N95.
N95 simply means it filters 95% of particles of a certain specification. It would be good for anyone exposed to any dust. N99 are used in some critical applications but are hard to breath through. N90 are less robust but are easier to breath through.
This one has a thin silicone flappy thing that shuts on inhale, opens on exhale.
If this mask is used long enough, the accumulated moisture drips out. So I think the non-valve version is probably the best, but is not in the N95 specification.
I almost wire this out for an errand but pfff – just used a scarf thing instead with careful breathing.
There was some discussion about footwear vis a vis going to stores.
I just remembered there’s disposable cloth shoe covers that are (or were) readily available at home centers for painting. Perhaps as a measure of caution, some of these covers could be used and disposed of after a grocery run.
Meanwhile, I worked out a method to run shoes through the washer. Put them in nylon garment bags and add scrap clothing to absorb the impacts to the interior of the washer. I happened to soak the shoes with isopropanol (outdoors)before the wash.
I had wanted to figure that out anyway.
Hope that helps.