Documented SARS-CoV-2 smear transmission?
May 11, 2020 4:00 PM   Subscribe

Have there been any documented cases of transmitting SARS-CoV-2 between people who did not share the same physical space?

For the purpose of this question, let's say documented means "reported in a scholarly paper or with at least a moderate amount of detail in a news source." No Twitter or anecdata, please.

The closest I have seen is asymptomatic carriers in Singapore who infected a person who sat in the same seat at church later that day. The other reports I read list the same methods of infection repeatedly: living together, hugging, being at adjacent tables at a restaurant, sitting next to each other in church, hands-on health care, etc. etc. I would have expected by now that there would have been a cluster where, e.g., a single food service worker infected a bunch of people through indirect contact or brief proximity.

I am not looking for physical distancing loopholes, merely trying to understand what the current state of documented transmission methods is.
posted by wnissen to Health & Fitness (7 answers total) 7 users marked this as a favorite
I recently read this scientist's blog post on some of the things we know about transmission and exposure.
posted by jb at 4:18 PM on May 11, 2020 [8 favorites]

I remembered reading a story about one woman who caught COVID-19 from a delivery package; it turns out she didn't, but she did catch it from a keypad at a pharmacy.
posted by capricorn at 4:25 PM on May 11, 2020 [3 favorites]

Via a shared salt shaker Germany, Reuters, in depth article. IDK if it's been papered yet though.
posted by unearthed at 4:30 PM on May 11, 2020

If I’m reading it correctly, the article with the salt shaker does not say that was the mode of transmission. It says that when the colleague turned to borrow the salt, the virus was transmitted between the two people, so that could be through breathing. It says they shared the salt shaker and the virus, not that the virus was passed through the shaker.
posted by FencingGal at 4:44 PM on May 11, 2020 [6 favorites]

In this March 12, 2020 post from the University of Minnesota Center for Infectious Disease, Study: COVID-19 may spread in several different ways, it is noted "In the 34-person COVID-19 mall cluster [CDC], researchers from Wenzhou, elsewhere in China, and in the United States say that the virus appears to have been transmitted indirectly, through the touching of contaminated surfaces, viral aerosolization in a confined space, or through contact with infected people who had no symptoms."

In this study, published by the Lancet on March 16, 2020, Investigation of three clusters of COVID-19 in Singapore: implications for surveillance and response measures, "Direct or prolonged close contact was reported among affected individuals, although indirect transmission (eg, via fomites and shared food) could not be excluded."

This March 17, 2020 NEJM Correspondence notes "Our results indicate that aerosol and fomite transmission of SARS-CoV-2 is plausible, since the virus can remain viable and infectious in aerosols for hours and on surfaces up to days (depending on the inoculum shed)."
posted by katra at 4:48 PM on May 11, 2020 [3 favorites]

The key word to search for is fomite. Most sources I've read say that fomite transmission is possible. Even so, I haven't seen any specifically documented cases of fomite transmission.

The blog post by Erin Bromage linked by JB above details the number of viral particles released by speaking, coughing, sneezing, etc, and discusses the typical number that would need to be absorbed to cause infection. Based on reading that, I assumed that transmission via inanimate object (door knobs, packages, etc) would be exceedingly unlikely. But in her write up, Dr. Bromage says, "Fomite transfer risk in this [bathroom] environment can be high."
posted by Winnie the Proust at 6:37 PM on May 11, 2020 [8 favorites]

This study suggests that indirect transmission via fomites or aerosols occurred in a mall, perhaps from elevator or restroom usage.
posted by RobotVoodooPower at 9:09 PM on May 11, 2020

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