An average person with the measles is likely to infect 12 to 18 others in an unvaccinated population. So what starts as an isolated case can rapidly become a full-blown epidemic.

An average person with the measles is likely to infect 12 to 18 others in an unvaccinated population. So what starts as an isolated case can rapidly become a full-blown epidemic. https://t.co/CQXtTmFWVu

— FiveThirtyEight (@FiveThirtyEight) February 17, 2019