Did the Centers for Disease Control and Prevention (CDC) actually “change their minds” this week about the potential risk of Covid-19 coronavirus being spread by contaminated surfaces? Not really. Not even on the surface.
Nevertheless, messages have surfaced on social media such as “the CDC doesn’t even know what it’s doing. Should be completely defunded like @WHO” and “These goons are still using the @CDCgov when they can’t even make up their minds” as well as the following:
Umm, completely de-fund the CDC? Isn’t that like saying “let’s get rid of this water supply thing” when there is not enough water in the middle of a fire?
Take a closer look at what the CDC has been saying specifically. Compare a previous version of a CDC web page (cited by the Fox News article accompanying the tweet above) with the current version. The exact wording may have evolved a bit. Nonetheless, in both versions, the CDC stated, “It may be possible that a person can get COVID-19 by touching a surface or object that has the virus on it and then touching their own mouth, nose, or possibly their eyes.”
Yes, both versions did include the following: “this is not thought to be the main way the virus spreads.” However, this statement does not say that contaminated surfaces cannot spread the virus. This statement does not imply that you should not worry about contaminated surfaces. In fact, the latest version added the following kicker, “but we are still learning more about how this virus spreads.”
Just because something is not the “main way” doesn’t mean that it doesn’t happen or that you shouldn’t be concerned about it. It’s just an issue of what may be more frequent. For example, using a toilet in a stall may not be the “main way” that you take dumps, unless, of course, you have built such a stall in your house or apartment for some reason. However, this does not mean that you shouldn’t be prepared to use a toilet in a stall. Not knowing what to do in a stall could lead to a messy situation.
Similarly, the CDC statements can simply mean that a majority of the Covid-19 coronavirus transmissions that have occurred so far have likely been via direct person-to-person contact. In most cases, direct person-to-person contact means that an infectious person coughs, sneezes, pants, sings, chants, curses, or otherwise breathes out virus-laden respiratory droplets, which then are inhaled by someone else. It is more a reflection of how contagious an infected person may be when you get too close to him or her. As I have written previously for Forbes, simply talking could expel fluid droplets that could hang in the air for over eight minutes. You may expel even more droplets whenever you use the “th” sound like when you say “shake that thang.” Imagine what could happen if these fluid droplets were carrying the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) .
Again, all of this does not mean that transmission cannot occur via contaminated surfaces. In fact, two scientific studies have shown that the virus can stay on surfaces for quite a while. In both studies, researchers applied the virus to various surfaces and then measured how the virus may degrade over time and how long the virus remained detectable. In the first study published in a research letter published in the New England Journal of Medicine, a team from the National Institute of Allergy and Infectious Diseases (NIAID), the CDC, Princeton University, and the University of California, Los Angeles conducted the study. Vincent J. Munster, Ph.D. from NIAID was the corresponding author for the publication so in theory you could call this the Munster study. In the experiments, the measured half-life of the SARS-CoV-2 was approximately 1.1 to 1.2 hours on copper, 5.6 hours on stainless steel, and 6.8 hours on plastic. The half-life is the time that it takes for half of initial amount of virus to no longer be detectable.
Then there was the study published as a research letter in The Lancet Microbe and conducted by a team from the School of Public Health at The University of Hong Kong (Alex W.H. Chin, Julie T.S. Chu, Mahen R.A. Perera, Kenrie P.Y. Hui, Hui-Ling Yen, Michael C.W. Chan, Malik Peiris, and Leo L.M. Poon). Their experiments found the virus to be detectable on:
- Paper for up to 30 minutes.
- Tissue paper for up to 30 minutes.
- Wood for up to a day.
- Cloth for up to a day.
- Glass for up to two days.
- Bank notes for up to two days
- Stainless steel for up to four days
- Plastic for up to four days
- The inner layer of a mask for up to four days
- The outer layer of a mask for up to seven days
This would be good news if your living quarters and all of your possessions happen to be made out of tissue paper. It could be bad news if you wear stainless steel underwear. In general, viruses tend to survive longer on surfaces that are hard and impermeable than those with lots of pores.
Note how long the virus may remain on and inside a face mask. This is why you should treat a face mask like a reversed pair of underwear. Be very careful when handling it. Avoid touching your face with the outside of the mask.
Certainly, these studies have their limitations. Just because a virus is detectable does not necessarily mean that there’s enough virus around to cause an infection. Viruses can be like holes in your underwear: a few may be OK, but once you get past a certain level, it becomes a problem.
Also these studies showed what happened under specific sets of laboratory conditions. As they say in commercials for hair dyes, your actual results may vary. Plus, different environmental conditions such as the surrounding temperature, air motion, and sunlight exposure could affect the survival of the virus. Thus, the numbers provided are only approximations and not exact time limits. In other words, don’t set a timer to determine when exactly you can start smearing money on your face and making moaning sounds. (By the way, smearing money on your face is rarely a good idea.)
Nevertheless, the results from these experiments do show that the virus can remain on surfaces for not an insignificant amount of time, which is a roundabout way of saying that the virus can stay on surfaces long enough to be a source of transmission. In fact, these experiments suggested that the SARS-CoV2 can remain on surfaces significantly longer than can other respiratory viruses like the influenza virus.
It is a well-established fact that various respiratory viruses can be transmitted via contact with surfaces. If you somehow don’t trust the CDC, just look at websites from other countries like the Canadian government. The Canadian Center for Occupational Health and Safety website states that “influenza viruses can also be transmitted by indirect contact by touching a contaminated object or surface and then touching your own mouth, eyes or nose before washing your hands.” It also indicates that flu viruses on such surfaces can remain “infective for two hours and maybe up to eight hours.”
Transmission via surfaces is known as fomite transmission. The “fo” part of this word is pronounced “fo” as in “fo’ sure” or “fi fi fo fum.” The “mite” sounds like “might” as in “you might not want to wear a cape in public.” A fomite is any surface or inanimate object that can passively carry an infectious microbe such as door knobs, remote controls, towels, dishes, or your significant other while you end up having to wash the dishes.
So, scientific guidance about surfaces has not really changed. You should still be concerned about surfaces that may be contaminated with the virus. You should still try to disinfect potential fomites. Nothing in the CDC statements about surfaces suggests that businesses were closed for “no reason whatsoever.” When a business is fully open, it can be challenging not only to keep surfaces virus-free but also limit direct person-to-person contact. After all, just look at how “well” people are social distancing with the recent re-opening of locations: