ProPublica is a non-profit investigative news organization that exposes abuses of power. Sign up to get our biggest stories delivered right after they’re published. In the early 1960s, American children lined up for the world’s first measles vaccines, yet it took nearly 40 years of strengthening immunization efforts before experts could officially declare in 2000 that the U.S. had eliminated measles. For the next 25 years, the country experienced outbreaks only when the virus was carried in by travelers from overseas. The resulting measles outbreaks no longer fade within a year. Those times are over. Starting in January of last year, measles ripped across the dry plains of West Texas, and since then nearly every state has reported cases. Two unvaccinated girls from Texas and one adult from neighboring New Mexico died before the West Texas measles outbreak appeared to die down last July. By that point, cases were emerging in Utah, yet state health authorities were unable to determine where the initial patients had contracted the virus. In that state, infections surged that fall and winter, persisting into May of this year. The Texas and Utah cases now lie at the heart of a highly technical — and politically charged — question: whether the United States will lose its measles-elimination status. Countries face no penalties for losing the designation, but it signals weaknesses in what were once robust vaccination programs, declining public confidence in vaccines, or both. To have any hope of retaining the status, the U.S. must convincingly demonstrate that measles did not circulate endemically — in a sustained person-to-person chain within the country for more than a year. For instance, if the Texas virus were to spread across the Southwest into Utah and keep infecting people there, that would pose a serious issue. However, if the Utah cases originated from a patient who contracted measles while traveling abroad, that would mark the start of a fresh transmission chain, effectively resetting the timeline. To investigate, the Centers for Disease Control and Prevention is examining the complete genetic sequences of the measles viruses found in those infected. In November, the then-head of the CDC stated that initial genomic sequencing indicated the Utah infections were not directly connected to the ones in Texas.
