Is “Superspreading” real? What does it mean, and how can we avoid it?

Infection and Spread

A: Yes, superspreading is as yucky as it sounds, and seems to have played an important role in early COVID-19 spread.

To avoid, stick to the Nerdy Girl stay SMART principles (Space, Mask, Air, Restrict, Time)!

This linked article gives an excellent overview of the superspreading clusters that have been identified and what we know about the science—please read.

Some highlights:

-Models based on contact tracing data estimate that between 10 and 20% of infected people may be responsible for 80% of SARS-CoV-2 spread.

-Nerdy girl caveat that superspreading events might be over-represented in the data since they are easier to identify than more casual individual encounters….but likely that the general conclusion is true.

-The virus spreads primarily via respiratory droplets produced by an infected individual during breathing and talking as well as coughing and sneezing. One thing that makes COVID-19 super sly is that people are infectious *prior* to having symptoms.

What is the recipe for a superspreading event?

-Closed, poorly ventilated space: Nearly (but not all) COVID-19 clusters were in indoor rather than outdoor settings.

-Large numbers of people: Very difficult to “superspread’ to a small group, and larger groups increase the chance that someone in the groups is infectious.

-Time: The longer the contact, the greater the likelihood of spread. More than 10-15 minutes seems to be one important threshold used in contact tracing.

-Droplet spewing: We’ve learned that things that project droplets, such as loud speech, cheering, heavy breathing & singing are more risky (like the Washington State choir superspreading event).

-Speech “superemitters’: Less hard evidence on this, but some people may naturally emit more respiratory particles during speech.

Looking ahead, things like cheering fans in sports stadiums and concerts will likely still be too risky for awhile (sigh…)

But the GOOD NEWS is that these estimates suggest that stopping superspreading events can go A LONG WAY towards putting out the fire of COVID-19 transmission, which gives us the best chance to resume many normal interactions in a safe way.

We’ve done a good job limiting large gatherings the last few months, but as things continue to re-open remember to stay SMART and don’t give the virus the super-spreading chance it’s waiting for!