Measles could become endemic in the United States if routine childhood vaccination rates continue to decline, with up to 51 million illnesses over a 25-year period, according to a new study. Although the disease is endemic in some other countries – meaning it happens regularly within an area or community – it was declared eliminated in the US in 2000 because of vaccination efforts with the highly effective measles-mumps-rubella (MMR) vaccine.

Measles, once virtually wiped out in the United States, could become commonplace again if declining vaccination rates continue, a new model shows.

Measles could be well positioned for a comeback in the United States in a very short period of time. If immunization rates continue to drop for a prolonged period of time, the US could see millions of measles cases over the next 25 years.