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/mFj9N1ok27

— FiveThirtyEight (@FiveThirtyEight) February 9, 2019