Person infected with a virus etc who transmits or spreads it to an unusually large number of people.

A person infected with a pathogen who transmits infection to an unusually large number of people. The term was first used during the SARS epidemic, to describe one individual who transmitted the virus to at least eight people. The R₀ for SARS was estimated to be around 3.

Virologists who researched superspreaders during the MERS outbreak said there are several reasons why these events, as they're called, emerge. Sometimes the virus mutates to become more contagious. Or some people just make more virus in their lungs.

According to a paper in The New England Journal of Medicine, "Super-spreading events have not yet been identified," for the new coronavirus, "but they could become a feature as the epidemic progresses."