When You Miss Superspreading, Everything Looks Like ‘Community Spread’ and Family Gatherings

Over the last couple of weeks, there seem to be a lot of political figures claiming how ‘community spread’ and family gatherings are leading to the rise in cases. There’s a definite political advantage to this: if the blame can largely be cast on inchoate factors and personal behavior, then political leaders don’t have to make difficult choices like shutting down places where transmission occurs.

But consider what a superspreading event would look like, if we didn’t know about the initial case. Consider this diagram of an Ohio outbreak (the original image wasn’t great):


The majority of cases (54/91) occurred during the superspreading event, and the household and extended family cases obviously wouldn’t have happened had (some of) those 54 people not brought the infection home with them. But imagine if we didn’t know about the superspreading event:


(Yes, I need a graphics department). In the absence of the known superspreading event, almost all of these cases would be chalked up to ‘community spread’ and spread among family members, including extended family. It bears repeating: those secondary cases among family members never would have happened without the index case.

Of course, there will be some actual community spread, and we know COVID-19 can rip through households–that’s why China quarantined people away from their families–but given how poorly contact tracing is working in the U.S. (and the absence of genomic surveillance for COVID-19), we’re likely missing many superspreading events.

Then again, if we did find those events, that might be very inconvenient for some people who then would have to make hard decisions.

Related: Saw this morning that the NYT makes some related points.

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1 Response to When You Miss Superspreading, Everything Looks Like ‘Community Spread’ and Family Gatherings

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