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K metric for COVID-19 shows there are superspreaders of the virus

(Photo credit: Getty Images)

LONDON — You probably know the R number. It’s the number of people a patient with a virus spreads it to.  Get the R below one, and the virus dies out.  The R is an average, however, of everyone who has the virus.  But to get the full picture of how the coronavirus is spreading through superspreaders, some scientists say you have to know the K.  

A BBC report from the London School of Hygiene and Tropical Medicine (LSHTM) details this metric.  The K measures the difference in how many the infected, infect.  For instance, the flu’s K is 2, which means people with it more or less consistently give it to 2 other people.  Even more reliable is a higher K, like 5 or 10.  There you can be sure that that illness is infecting a similar number of people.  The report says that the coronavirus K has a low K of .16, meaning there are “?a lot of variations between people,” and that some people are Superspreading.

Following on the WHO’s announcement that said asymptomatic carriers rarely spread the virus, LSHTM’s Dr. Adam Kurcharski says, “Typically, what happens is a lot of people don’t [give it] to anyone. Then there’s a handful of events where you see large amounts of transmission happening with five, 10, 20 people potentially infected.” 

The report says the traits of a superspreader can be varied:  They might be someone with severe symptoms, a nurse with insufficient PPE carrying a higher viral load, or someone that goes to a mass gathering and doesn’t socially distance.  Cruise ships and care homes have been superspreading venues.   

In theory, identifying superspreaders and superspreading behavior can help with easing some of the restrictions of lockdowns, while still vigilantly canceling big public events. 

The BBC reports that data shows just 10 to 15% of people are behind 80% of all infections. 




How To Prevent the Spread of COVID-19 Coronavirus 


COVID-19 coronavirus is transmitted from person to person. It is a virus that is similar to the common cold and the flu. So, to prevent it from spreading: 

  • Wash hands frequently and thoroughly, with soap and water, for at least 20 seconds.  
  • Don’t touch your face. 
  • Keep children and those with compromised immune systems away from someone who is coughing or sneezing (in this instance, at least six feet) 
  • If there is an outbreak near you, practice social distancing (stay at home, instead of going to the movies, sports events, or other activities.) 
  • Get a flu shot. 

Resources for more information: 



State of Utah: 

Utah State Board of Education 

Utah Hospital Association 

The Church of Jesus Christ of Latter-day Saints 

Utah Coronavirus Information Line – 1-800-456-7707 

National Links 

Centers for Disease Control and Prevention 

Commonly asked questions, World Health Organization 

Cases in the United States