The US is having its largest measles outbreak in in 25 years — here's who needs another dose of the vaccine

More than 750 measles cases reported so far this year are the largest outbreak of the disease since the mid-1990s.The majority have been among unvaccinated children, but as many of 10% of those affected are adults who have already gotten at least one dose of the vaccine.Visit Business Insider's homepage for more stories.(Reuters) - The United States is in the midst of its largest measles outbreak in 25 years, with the disease mainly hitting people who have failed to receive the recommended two doses of the live measles vaccine.The US Centers for Disease Control on Monday reported another 60 cases, bringing the total for 2019 so far to 764.Twenty-three states have reported cases this year, the latest being Pennsylvania. New York has had the most cases so far — the 60 reported last week included 41 in New York City and 11 in nearby Rockland County, mostly in unvaccinated people in Orthodox Jewish communities.While the vast majority of measles patients are unvaccinated children, up to 10% of patients in the current outbreak are adults who received at least one dose of the measles-mumps-rubella vaccine.The US Centers for Disease Control and Prevention has issued recommendations on when adults may need to seek an additional dose of the MMR vaccine: