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One number can help explain why measles is so contagious

A disease’s R0 is the average number of people a person can infect in an unvaccinated population

child scratching measles rash

GOING VIRAL  Measles is extremely contagious. And one number, or rather a family of numbers, sums up the risk of its spread.

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By Helen Thompson

- More than 2 years ago

Two ongoing outbreaks have dominated headlines in the past few months.