As of June 13, the U.S. has recorded 1,044 cases in 28 states this year, the Centers for Disease Control and Prevention said Monday — the highest number since 1992, when 2,196 cases were reported for the year. Why it matters: Measles was declared "eradicated" in the U.S. in 2000, years after the development and implementation of the MMR vaccine, which is 97% effective with 2 doses. But the extremely contagious virus has crept back into American society, mainly via pockets of communities who refuse to use the vaccinations, experts have told Axios.Before widespread vaccination, roughly 3 to 4 million Americans got measles each year, leading to an estimated 400–500 deaths and 48,000 hospitalizations, per the CDC.The highest number of annual cases in the U.S. recorded by the CDC since 1942 was in 1958 when 763,094 people reported infections.Go deeper: The return of measlesExperts sound alarm on measlesGlobal risk worsens as anti-vaccination campaigns spread