Viability of Covid-19 virus on various surfaces (hint: use gloves when handling Amazon packages and don’t open them for 24 hours)

March 20, 2020 • 10:30 am

Reader Charles sent me a linking to a publicly-available article from the New England Journal of Medicine that measured the viability of the Cov-19 virus (they call it SARS-CoV-2, or “severe acute respiratory syndrome coronavirus-2”) on various surfaces, comparing it to the viability of a closely related coronavirus, SARS-CoV-1.  You’ll remember the second virus from a while back since it was the cause of SARS. As the NIH notes:

SARS-CoV-1, like its successor now circulating across the globe, emerged from China and infected more than 8,000 people in 2002 and 2003. SARS-CoV-1 was eradicated by intensive contact tracing and case isolation measures and no cases have been detected since 2004.

The very short article is intelligible to laypeople, and you can see it here or by clicking on the screenshot below. The full reference is at the bottom:

To measure the viability in aerosols, the virus was nebulized (put into an aerosol form of small droplets), and squirted into a “Goldberg drum,” which rotates and keeps the nebulized material in the air for a long time.  Here’s one of those drums from ResearchGate:

At various intervals, the infected material was sampled and tested for virus viability (aerosol from the drum or virus sprayed on surfaces of copper, cardboard, plastic, and stainless steel). The remaining amount of virus capable of causing infection was measured as the TCID50, or the amount of sampled material required to cause infection in 50% of tissue-cultured material. This figure drops over time as the virus dies.

The main lesson comes from the figure below, which gives, in the three rows, the decay of viable virus over time, the regression plots (on a log scale) predicting the decay over time, and the estimates of the half-life of the virus in aerosols and on various surfaces based on assuming an exponential decay rate of the virus quantity.  The virus of interest, SARS-CoV-2, is shown in red, and its relative the SARS virus (SARS-CoV-1) is in blue.

Have a gander. I’ve put the journal’s caption below the figure for mavens, but summarize the results below that:

Figure 1. Viability of SARS-CoV-1 and SARS-CoV-2 in Aerosols and on Various Surfaces. As shown in Panel A, the titer of aerosolized viable virus is expressed in 50% tissue-culture infectious dose (TCID50) per liter of air. Viruses were applied to copper, cardboard, stainless steel, and plastic maintained at 21 to 23°C and 40% relative humidity over 7 days. The titer of viable virus is expressed as TCID50 per milliliter of collection medium. All samples were quantified by end-point titration on Vero E6 cells. Plots show the means and standard errors ( bars) across three replicates. As shown in Panel B, regression plots indicate the predicted decay of virus titer over time; the titer is plotted on a logarithmic scale. Points show measured titers and are slightly jittered (i.e., they show small rapid variations in the amplitude or timing of a waveform arising from fluctuations) along the time axis to avoid overplotting. Lines are random draws from the joint posterior distribution of the exponential decay rate (negative of the slope) and intercept (initial virus titer) to show the range of possible decay patterns for each experimental condition. There were 150 lines per panel, including 50 lines from each plotted replicate. As shown in Panel C, violin plots indicate posterior distribution for the half-life of viable virus based on the estimated exponential decay rates of the virus titer. The dots indicate the posterior median estimates, and the black lines indicate a 95% credible interval. Experimental conditions are ordered according to the posterior median half-life of SARS-CoV-2. The dashed lines indicate the limit of detection, which was 3.33×100.5 TCID50 per liter of air for aerosols, 100.5 TCID50 per milliliter of medium for plastic, steel, and cardboard, and 101.5 TCID50 per milliliter of medium for copper.

The lessons:

1.) The new virus has a decay rate about the same as the old SARS virus—except on cardboard. The new Covid-19 virus decays completely on cardboard after 24 hours, but the earlier virus is pretty much gone after only eight. What this means is that if you get a cardboard package in the mail from a place like Amazon, either have it left outside your door or, if you’re worried, handle it with gloves and then don’t open it for at least a day.

2.) On stainless steel and plastic, the new virus will be almost completely gone after four days, and on copper in about 8 hours. This means that if you’re holding onto stainless steel or plastic, as in subway straps or poles, or steel banisters, you could be infected even several days after an infected person touched those surfaces.

3.) The new virus in aerosols was even less viable than on cardboard, with both old and new viruses having a half life of one hour (i.e., after 8 hours the infectability has been reduced by 256-fold). But still this means that if you walk through a space in which an infected person has sneezed or coughed an hour or two beforehand, you could get infected.

The main lesson is to avoid being near people sneezing and especially coughing, and wash your hands ASAP if you’ve touched anything suspicious. And, of course, DO NOT TOUCH YOUR FACE. I’ve been practicing that and, I think, have gotten pretty good, though we all touch our faces unconsciously.

Here’s a photo from the NIH, showing the virus erupting from cells. The caption: “This scanning electron microscope image shows SARS-CoV-2 (yellow)—also known as 2019-nCoV, the virus that causes COVID-19—isolated from a patient in the U.S., emerging from the surface of cells (blue/pink) cultured in the lab.NIAID-RML.”


van Doremalen N. et al. 2020. Aerosol and Surface Stability of SARS-CoV-2 as Compared with SARS-CoV-1. New England J. Med. March 17, 2020; DOI: 10.1056/NEJMc2004973.

82 thoughts on “Viability of Covid-19 virus on various surfaces (hint: use gloves when handling Amazon packages and don’t open them for 24 hours)

  1. If you wash your hands and don’t touch your face, even if you get the virus on you, you won’t contaminate yourself. I’ve been opening packages then disposing of the cardboard. Then I through wash my hands with soap and water.

    1. So far i have been doing the same on the assumption that viruses sealed in the package have had time to die off.

      1. I usually do this anyway but now I’m more mindful to not touch anything until my hands are washed and if I forget to wash down those surfaces with alcohol & a soft cloth. I wash my hands all the time throughout the day anyway as I pee a lot because I want to stay hydrated! I am using a combination of a thick balm I usually use on feet & the moisturizing cream I used during radiation treatment (so that stuff is thick).

    1. I think you would want to wash your hands after handling the mail and or the mail box. Just like the boxes delivered by UPS or Fedex. Keep lots of the latex gloves around to handle this stuff and then throw them away. Having cats we use these gloves all the time anyway dealing with the litter.

    2. Colin, I am using gloves to get the mail. One should be enough on one hand.

      Dump it in a bag and let it sit for a couple of days before opening it.

    1. Very interesting, but we are not in a position to actually determine the optimal moment of intervention. Hence, as the author indeed suggests, ‘continuous control’ is about all we have.

  2. Ha! This occurred to me a couple of days ago. Also, leave the contents for a day or so as you don’t know who handled them.

  3. We’re all going to be living like Carol White in “Safe” by March 31st.

    Don’t forget about the vector potential of the mailbox lid, regardless of whether there’s any mail.

  4. Well if packages are are a contamination problem then we need to think about the letters that come through the mail to us daily🤷‍♂️

  5. There’s some virtue in listening to AM news radio. A few minutes ago, I turned the dial to find a radio station that wasn’t playing the latest Trump press conference with “Tony” and “Deborah” and I happened to hear the news that a team at UCSF has just finished mapping the human proteins that are attacked by covid-19. “Just” meaning hours ago. Usually takes years. Here’s the audio report:

    1. There are also reports that several vaccine trials are about (matter of weeks) to start, in US, UK, Germany, China.

      In fact, someone in Seattle has already received the first vaccine shot from US biotech Moderna. So a time frame of June-July is not unreasonable to see if a vaccine is safe and works. Then, of course, gearing up manufacture, etc.

      With luck!

      1. The last I heard was still a year before mass inoculation. But, it doesn’t hurt to hope for more speed.

        I’ve heard, too, of a quinine medicine and another off the shelf medicine for treating the virus. These have not been proven yet. I suppose they might lessen symptoms. Keep your fingers away from your face and crossed behind your back.

        1. I read 12 months too.

          Moderna got a phase 1 trial started (with mRNA-1273, I think) in amazing time, but I think it’s the slow step now.

  6. It’s good to know people are studying these issues. The post office claims they have notified all mail carriers to wash and be careful with delivery. They claim they disinfect all handling equipment frequently. I’m not confident that’s going to be totally effective. I use gloves when bringing in the mail and opening it. Letting a cardboard box delivery sit for 24 hours sound like a good idea.

    1. But UPS isn’t doing diddly squat to protect their workers. According to a news report I just read, they aren’t giving drivers hand sanitizer and instead just told them to wash their hands whenever possible… I’m sure there are lots of opportunities to do so, right? And they are still delivering person to person in big businesses, including, as one driver pointed out, health care facilities like retirement homes and such. As he also stated, he has about 120 stops, 300 packages, and thus lots of opportunities to spread the infection.

      1. The latest research, just published, tested surfaces and found the virus lasts only 24 hours on cardboard. That should help with cardboard packaging delivered to your door. Metal surfaces – up to 9 days.

  7. Just a quick note on a related subject, my daughter reports her veterinary clinic is in chaos because the owner is MIA and very careless. Two technicians are coming in while sick with cold or flu-like symptoms. In addition, they are planning flights to other states on the weekend to visit relatives. With nobody in charge the emergency plan written up by my daughter is simply being ignored. She has decided to stay home for the duration. The lesson here is, don’t assume if you feel you have to visit some public facility that the people there are taking the same level of precaution that you are. Many are simply in denial and will end up spreading the virus and, inevitably, causing unnecessary deaths.

    1. So are you saying that some people aren’t taking any proper precautions, like how last night when I stopped at my local gas station, just off the highway, and I saw one clerk vigorously rubbing an itch on her face with her gloved hands, and the other bored clerk blowing into his glove, making it inflate and deflate like a balloon, stuff like that? I wish I were making this up or exaggerating for effect, but I’m not.

    2. I am very afraid for America. The lack of direction and the kids down in Florida for Spring Break. I think this is going to be very bad for you in the coming weeks.

      1. Granted you’ll get nothing of value from the president. You’d think the governor or somebody would close the beaches. Where are all the adults around here?

      1. Everything except shining UV-A containing light (let alone B or C) as if it is as harmless as a plain old flashlight. I cringe at this practice, and more when the counter arguments are 1. it’s everywhere and 2. it makes vitamin D.

        But i apologize for ranting.

        1. I didn’t know there was an issue with the UV. I was a bit concerned about the chemicals being dusted on the kids as if it was talcum powder on a baby’s bum.

          1. UV is important to know about. It is invisible light, coming right after “violet” in energy, increasing from UV-A to UV-B to UV-C. UV-C is the highest energy. I refrain from details here, but suggest Wikipedia. The lamp or bulb manufacture results AFAIK in a spectrum of light, so not necessarily 100% of one band. Hence the violet glow of “blacklights”, which are usually offered in auto parts stores with UV goggles e.g. for finding leaks of antifreeze or refrigerant from cars. Factors to consider for exposure include duration, frequency of exposure, light wavelength, light beam angle, light source distance, etc.

            I’ll get a little more emphatic and assert : UV is not a toy.

  8. I have a question. Restaurants are closed but take out is going gang busters. I personally worry about possible infection through food preparation and handling, and take out involves that. Does any one know if my worry is justified? If so, should not take out be shut down too?

    1. I know. I can live without take out food until we have this sorted. Good grief I always assumed that’s the biggest contagion. People are still getting their take out coffee and not even taking off the lid. It’s like no one knows viruses enter mostly through the mouth, nose, and eyes.

    2. I also wonder if nuking the food well will kill this virus.

      I find it challenging to sanitize my groceries! Canned goods are easily Lysoled or left alone for days. But fresh veggies and fruit? I’ll be washing fruit with soapy water and veggies with a dilute vinegar-water solution like I generally do, but I doubt the latter does anything to this virus. What to do?!

      1. The soapy water sounds like the way to go. Lots of videos explain how soap dissolves the virus’s fatty coating. Unlike hands, one can leave the fruit and veggies in the soap for a few minutes without it soaking in so much that it changes the flavor. That’s my guess anyway.

        1. When you say “fatty coating,” I think Dawn dish soap. I’m glad that’s the only one I’ll use.

          One comment, irreverent: I just wiped down my delivered groceries with a rag and Clorox Clean-up (the best I can do before I get gloves, which I hadn’t gotten because these issues were not around last week), and I wiped down the ice cream and put it in the freezer. Then I remembered how corona thrives in cold temps. I bet the CDC isn’t researching the safety of my ice cream.

          Third point: CDC and Dr. Fauci (I think, on MSNBC) say that simple rinsing of things like lettuce is sufficient. I hope that holds to be true.

          1. I’m afraid we’re on our own with some of these edge cases. Unless we’re willing to walk around in a bubble, we’re really counting on infected workers in the supply chain staying home. It’s a crap shoot really. We’re all trying to lower our chances of getting infected but it would be hard to get it to zero.

      2. I just saw the report on the virus wrt surfaces. Metal, 3 – 9 days; cardboard 24 hours. The recommendation is to leave delivered cardboard packages alone overnight before opening them. I do my regular mail in-processing with gloves.

    3. The risk is significantly smaller if it’s just serving staff. Six people in a kitchen that is properly sanitized is far less dangerous than crowded dining areas where dozens of strangers pass through every hour.

      Ultimately all your food is going to be handled at some point by a person, whether it comes from take-out or the grocery store. There’s no way to get down to zero risk.

  9. (Post before reading)

    I am wondering the minimum of particles and in how much of a swipe and in which mucous membranes (eye, nose, mouth… ear?..) will result in an infection

  10. I heard about this study the other day on the podcast, this week in virology (twiv) conducted by a couple of senior Columbia virologists of jerry’s and my generation. Most of the discussion can be understood by the general listener like me. They have been doing these podcasts weekly for about ten years now, and several podcasts a week for the past couple of weeks and all are archived. Yesterday was episode 592 and can be found at. each podcast lasts from one to two hours and they are open to comments by email.

    1. Somehow, being 200 miles away from that particular idiot still seems too close for comfort. Granted, I’m probably surrounded by morons who believe similar stupid racist things. I try not to mingle with the locals.

  11. There needs to be a global outcry over China’s (other Asian countries too) behaviour/practices which has caused all of this.

    They are causing the slaughter of Rhinoceroses due to their primitive superstition that their horns have magical properties They are causing the slaughter of bears due to their primitive superstition that bear paws have magical properties. It is they that are causing the slaughter of Sharks due to their insistence on having shark-fin soup, and now we have this Covid 19 virus due to their heartless, cruel, torturous treatment of animals – including domestic cats & dogs – in these wet markets. It is time they abandoned these old, barbaric ways and joined modernity.

    Please watch this in its entirety:

    1. Oh, absolutely. I agree that China MUST change their cruel, unhygienic, immoral, and illegal wet market practices, raiding every conceivable ecosystem for wild animals, endangered or not, cramming them into cages one atop another with complete disregard for the health of the animal, the international laws, or basic human decency. I don’t need to watch anything new to know this. The images I’ve seen in the past still haunt me. My only issue is the notion that, as the idiot from Kansas thinks, only Chinese can get the virus or only the Chinese can spread the virus, or as tRump thinks, only the Chinese have a responsibility to stop the spread of the virus. I don’t deny their responsibility for unleashing it on the world.

          1. My Wikipedia recollection is :

            Jinping assumed position in 2012. Hu Jintao was in that position during the SARS problem in 2005-ish.

  12. Being older I’ve been taking precautions with anything that is delivered. I’m sterilizing things with an industrial strength ozone generator, The wimpy ones normally sold for personal use are insufficient with too low an ozone concentration. Needless to say, ozone at these concentrations will damage your lungs, so it must be used carefully in a location where people are not exposed to the air.

    1. Do you know for sure that ozone is deadly to COVID-19? I would worry that it is only toxic to things that breathe and, AFAIK, viruses do not. I’m no expert but I’m curious.

      1. It works very well killing both viruses and bacteria as well as mold because it’s a very strong oxidant. It’s better than chlorination for water treatment,so newer treatment plants often use ozone. Again, commercial generators should not be used when they contaminate living spaces. I got my unit when we had overland flooding that wet our basement. I sealed it up and treated it with ozone while it dried. We had no mold problems.

  13. It’s not easy to find Google results about how to clean hands when soap, water, or any other accessory is available. But I seem to recall that the Red Cross publishes guidance on this matter : rub your fingers and thumbs on clothing to get them as hot as possible, for a while.

    I’d like to find a publication on that.

    1. Yeah I posted that to my FB a few days ago as evidence that this is serious & not just killing “old people”.

      1. And now Illinois has its own “stay in place” order – well, I guess that will settle the question posed here.

      2. From “Community Transmission of Severe Acute Respiratory Syndrome Coronavirus 2, Shenzhen, China, 2020”, Jiaye Liu et. al.

        “We found a sharply increasing proportion of infected children (from 2% before January 24 to 13% for January 25–February 5; p<0.001), implying that increased exposure for children and intrafamily transmission might contribute substantially to the epidemic."

        That early 2% figure that keeps getting quoted everywhere, and is cited as justification for a policy of no school closures in Australia, is almost certainly an artefact of the early outbreak working its way through work places before getting loose in the general population. I've seen more recent studies from China that suggest over 18 percent of patients are under 20 years of age. But it does seem to be less severe in children older than 1 than in adults. Case fatality risk is about 0.1% according to "Our World in Data". CFR of 0.3% for 20-49 year olds, about 16 times higher than for seasonal flu.

        1. Yes and even if it doesn’t kill you you are risking permanently damaged lungs or later perhaps a heart attack from pneumonia. At a minimum, who wants to get sick? I had a flu over Xmas holidays. I had a milder version because I had the flu shot but it was miserable. I was so congested and sore for 3 weeks & couldn’t leave the house, managing mostly to lounge around & listen to books. It triggered such severe migraines they brought me to tears. So, no thank you I’d rather pass on an illness, even a mild version.

  14. UVA is just under visible. UVB gives you sunburn. UVC is what’s used in sterilized like I have in my fish tank. Those are much more dangerous. These sterilizer lights are covered & have a cut off so if you open the unit, it cuts power to the UV light because you don’t want to expose your eyeballs to that light.

      1. If you’re wondering if UV is used in the process of sterilization of equipment – the answer is, generally, yes. Specifics matter though – microbiology labs, dentists offices, etc. might have specific conditions in which UV – again, of a specific type – might work – and might not.

  15. You can always mix a little bleach and water in a spray bottle and mist the suspect packages before opening.

    Even as we are having a bit of bad luck, one lucky happenstance occurred. About three weeks before the kerfluffle, my wife’s practice had a bunch of packages of antiseptic wipes that had “expired”. They were going to toss them, but I took them hoping to put them to some use.
    We have found a use for them…
    The only problem is that the fumes are a bit strong compared to the civilian stuff. But they are intended for cleaning spaces known to contain infectious agents.
    Several times a day, I go around and wipe down all the door knobs, faucets, and light switches.
    We have a special tub of bleach water in the kitchen that any dishes my wife touches go into to soak, although she is mostly using paper plates and plastic cutlery.

    Also- five days and no test results yet. It does not really matter how many test kits are distributed, if there is a backlog at the labs doing the analysis.
    I suppose we can all take comfort in the fact that actors and professional athletes are getting their results back in a timely manner, especially the ones who are not showing any symptoms, but just feel they should be tested.

  16. Some of my colleagues showed that many viruses survive passage in sewage, and I imagine that COCID-19 is one of them. (Wordsearch Shinola in that paper to find what they used for a control, but I digress.)

    I wonder if it might be useful to monitor raw sewage input at treatment facilities to get a rolling index of the prevalence of the virus in a given area? Something like that ought to cut through the problem of unreported as well as asymptomatic cases.

    1. Maybe the concentrations would be too low to measure. Interesting idea though.

      One study shows the virus lingering in some patients for 37 days after “recovery”! Wicked little beastie.

  17. Thank you for sharing this!

    You say…

    “…squirted into a “Goldberg drum,” which rotates and keeps the nebulized material in the air for a long time.”

    and then

    “this means that if you walk through a space in which an infected person has sneezed or coughed an hour or two beforehand, you could get infected.”

    But in real life, wouldn’t the droplets fall to the ground, since there’s nothing to keep it in the air for a long time (like the Goldberg drum does)? Aren’t the droplets too heavy to sit in the air at home or outside?

    1. Interestingly, the droplets stay suspended in cool dry air longer than in warm humid air explaining why flu and, hopefully, coronavirus, is transmitted more readily in winter than summer. Summer, come soon.

    2. I swear I got the flu over Xmas when someone in a hospital lobby just sneezed and didn’t make an effort to sneeze into hand or sleeve. Jerk! This is the risk going out right now. Some ass infecting me. I really want to avoid all contact as much as I can.

      1. My brother-in-law is an MD. He advises all his immunosuppressed patients to cover their face with anything – like a towel or scarf when they pass through the hospital. Makes sense. Also for anyone who works there, I would think.

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