Let’s survive the coronavirus pandemic

Can I catch covid-19 from boxes, objects from the store, letters, etc?

As we all know, people can catch covid-19 by touching door knobs, light switches, faucet handles, payment screens in stores, etc., and then touching their faces. This is why we should wash our hands frequently and avoid touching our faces. Sometimes it’s even a good idea to wear disposable rubber gloves.

So there’s no question that the virus can survive on objects and that we can get infected from touching those objects.

But do we need to worry about delivered packages and items we buy in stores? If we order something from Amazon and the UPS driver leaves it on our porch, do we need to be concerned about touching the box? What about the items inside the box? What about food?

The answer is yes, in some cases we need to be concerned. The CDC says we don’t but I just read the following paper — it’s new — and I think the CDC is wrong:

Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1

Also see this preprint published a few weeks later:

Stability of SARS-CoV-2 in different environmental conditions

These scientists found that at room temperature, the covid-19 virus lived up to 72 hours on plastic and stainless steel, 24 hours on cardboard, and 4 hours on copper.

Temperature is significant because it’s almost certain that the virus lives longer when temperatures are lower, as suggested by the following papers:

Effects of Air Temperature and Relative Humidity on Coronavirus Survival on Surfaces

Persistence of coronaviruses on inanimate surfaces and their inactivation with biocidal agents

Suppose a UPS driver leaves a cardboard box on your porch. You might think, “I’ll leave it here for 24 hours, and then it will be safe to handle.” Not necessarily. If it’s cold outside, the virus might live longer than 24 hours.

And what about a milk carton that stays refrigerated from the moment it leaves the bottling plant? According to the research cited above, some viruses can live more than 28 days at that temperature. Maybe SARS-CoV-2 can too. We don’t know yet.

Coming soon: how to disinfect things.


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