What is the superspreader effect in outbreaks?

The superspreader effect refers to a small proportion of infected individuals driving a disproportionately large number of transmissions in an outbreak.

What percentage of people are estimated to be superspreaders?

Scientists estimate that for a typical outbreak, 20% of infected people may be responsible for driving 80% of the infections.

Why do virus concentrations vary so much between infected people?

Virus concentrations can vary enormously between infected individuals, with some having millions of times more virus than others.

Home / Health / Outbreaks Driven by 20% of People: The Superspreader Effect

Outbreaks Driven by 20% of People: The Superspreader Effect

29 Jan

•

Summary

A small group of infected individuals drives the majority of transmissions.
Twenty percent of people may cause eighty percent of infections.
Virus concentrations can vary dramatically between infected individuals.

Outbreaks Driven by 20% of People: The Superspreader Effect

Emerging research indicates that a small percentage of individuals act as 'superspreaders,' disproportionately driving infectious disease outbreaks. This phenomenon is not new and applies to various respiratory pathogens, including flu, RSV, tuberculosis, and measles.

Scientists have identified a mathematical pattern, estimating that approximately 20% of infected people could be responsible for up to 80% of transmissions in an outbreak. This suggests a significant concentration of infectiousness within a subset of the population.

Furthermore, studies reveal extreme variability in the amount of virus present in an infected person's respiratory fluids. Some individuals may carry up to 10 million times more virus particles than others, with concentrations reaching a billion virus copies per milliliter at the higher end. This wide range in viral load likely contributes to superspreading events.