- An average person with the coronavirus infects about two other people, but sometimes an infected person passes the virus to far more people during a "super-spreader event."
- There have been reports of super-spreader events in South Korea and the US that have sparked local outbreaks.
- Most super-spreader events are similar: The infected person attends an indoor gathering with lots of people, like a religious service, choir practice, or birthday party.
- The commonalities of these events inform health officials about the types of gatherings with the highest chances of facilitating the virus' spread.
In mid-February, a 61-year-old woman attended church services in Daegu, South Korea. Soon after, she tested positive for the coronavirus — then so did dozens of others. South Korea's coronavirus case count quickly jumped from 29 cases on February 15 to more than 2,900 two weeks later.
Throughout this pandemic, clusters of coronavirus infections like this have cropped up almost overnight, sprouting outbreaks that spiral out of control. Such spikes in cases can often be traced back to a super-spreader event like the one in Daegu, in which one person infects an atypically large number of people.
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During the last two decades, super spreaders have started a number of measles outbreaks in the United States," Elizabeth McGraw, an infectious-disease expert from Pennsylvania State University, wrote in The Conversation in January. "Sick, unvaccinated individuals visited densely crowded places like schools, hospitals, airplanes and theme parks where they infected many others."
Research has found time and again that the risk of the coronavirus spreading is much higher indoors, in poorly ventilated spaces where lots of people have sustained contact. That's because it primarily spreads via droplets that fly through the air when an infected person coughs, sneezes, or speaks.
A preliminary report from scientists in Japan (which has not been peer-reviewed) suggested that the odds that an infected person "transmitted COVID-19 in a closed environment was 18.7 times greater compared to an open-air environment." Another preprint study examined 318 outbreaks in China that involved three or more cases and found that all but one involved the virus jumping among people indoors.
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Singing and projecting your voice might be particularly risky activities, since that can send droplets farther than the recommended 6 feet of social distancing.