[ Question ]

Can Covid-19 spread by surface transmission?

by Raemon1 min read10th Jun 20209 comments

68

Coronavirus
Personal Blog

I've seen a lot of claims lately that coronavirus doesn't spread on surfaces, and therefore we can stop worrying about packages (and probably takeout food, even uncooked?). 

My understanding of the claim is something like "we just haven't actually seen any evidence of surface transmission, despite the entire world paying attention, therefore it probably doesn't happen."

It's a bit trickier to prove a negative, but can anyone who either strongly believes that covid can't spread via surfaces, or who believes that it can (at least sometimes), write up the reasons for their beliefs? 

New Answer
Ask Related Question
New Comment

4 Answers

There are at least a few cases where people later entered a (now empty) room that covid positive people had been in recently and later got covid with no other obvious transmission mechanism. Now, they could of course gotten it some other way, so this is only suggestive. The cases I heard about were elderly people who may contract covid with a smaller viral load.


Edit: I did not see if those cases looked into whether there was air being circulated in said locations, which would provide a different vector than surfaces.

This seems neglected given that it is impacting the behavior of billions of people right now, perhaps needlessly.

Evidence for surface transmission seems to exist: according to this article + report, staff in a hospital did not get infected themselves, but probably caused transmission between patients via non disinfected medical tools https://www.sciencemag.org/news/2020/05/study-tells-remarkable-story-about-covid-19-s-deadly-rampage-through-south-african

It can *survive* on surfaces for a long enough period of time for it to seem possible. But I think viral load is important and it might not practically be a serious vector for most people and most surfaces, particularly those that are commonly disinfected. It's amazing how our knowledge went from symptomatic/surface? to pre-symptomatic/aerosol? transmission.

It seems unlikely that it is literally impossible (are any respiratory viruses not able to be transmitted via surfaces?), but everything I've seen suggests that we should be *way* more concerned about aerosol/air transmission. Maybe this is the wrong way to look at it, but I guess I figure if someone has left small amounts of the virus on a surface, they've also been breathing in that area, and probably left a lot more of it in the air. So if I'm near that surface, I should be more worried about the air by far. Especially since most masks aren't going to block it completely, and getting it on my hands doesn't necessarily mean I get it into my body, whereas breathing it in does. I suppose it lingers longer on surfaces, but it seems to be pretty weak pretty fast. And a person spreading the virus doesn't necessarily get it all over his or her hands or surfaces, since people don't seem to have a ton of sneezing/runny nose/heavy coughing going on compared to other diseases. So the only time I'd be thinking about surfaces is dealing with a package delivery or touching something outside.

And I've long stopped thinking about that. I find it impossible to completely disinfect everything that touches the outside--I lose track of everything that might have touched everything else--so I've stopped caring about surface transmission, beyond some basic handwashing. Plus it's hard to even replace my cleaning supplies in the stores. So far, I'm pretty sure I haven't had it, but I could have been asymptomatic. And I've been regularly going to a popular Dunkin Donuts with a mask but not being very fastidious about washing my cup and donut bag and straw and phone and keys and headphones and jacket every trip. Very early on, it was said surfaces probably weren't the main vector, so I was always annoyed with the push for gloves over masks.

I realize that this decision has no bearing on whether I could contract it from surface transmission, but it seems impossibly difficult to worry much about it, especially given how many resources seem devoted to cleaning things, especially outside, when we know so much of the problem is airborne. I wonder a lot about A/C use in the coming months and why we don't have that discussion. And if viral load matters, that would be good to know. I fully expect to get the virus, as I have from the beginning, at some point in my life.