The CDC reported 695 measles cases as of April 24, which marks the highest annual total since U.S. health officials declared the disease eradicated in 2000.
This figure surpasses the previous record of 667 cases set in 2014.
Measles infections have occurred in 22 states this year. Most are linked to outbreaks in New York and Washington state, which started after international travelers brought the virus back from countries like Israel, where major outbreaks are occurring.
"The longer these outbreaks continue, the greater the chance measles will again get a sustained foothold in the United States," the CDC said in an April 24 statement.
HHS Secretary Alex Azar also reaffirmed the measles vaccine's safety April 24 and said HHS will roll out a major campaign to reinforce positive vaccine messages next week, in honor of National Infant Immunization Week.