The U.S. has reported 1,288 measles cases this year — the highest number in 33 years, according to the latest figures from the Centers for Disease Control and Prevention. The last time the U.S. saw more measles cases was in 1992, eight years before the disease was declared eliminated in the country.
"We're seeing a lot more measles transmission than we are used to," says Caitlin Rivers. She's the director of the Center for Outbreak Response Innovation at Johns Hopkins University, which has its own measles dashboard.
"Measles is one of the most infectious diseases known to humans. And more importantly, it's preventable. And so we really hate to see this resurgence of a preventable virus," Rivers says.
Since the start of the year, measles cases have been confirmed by more than three dozen states plus the District of Columbia. The largest outbreak by far is in Texas. The state has reported 753 measles cases this year. Across the U.S., 155 people have been hospitalized, and three people have died.
And while the Texas outbreak has slowed significantly, across the country, Rivers says the U.S. is now seeing more cases on a weekly basis than in previous years.
The Texas outbreak started in January. At one point, Rivers says, the state was reporting 15 to 20 new cases of measles per day, raising fears that, if the outbreak continued the U.S. would lose its "elimination" status, which is a technical term in public health that means the disease has not had a constant transmission for a 12-month period or longer. She says that's less likely to happen now, given that the state is only reporting a handful of cases per week.
But that doesn't mean it won't happen in the near future, says Dr. Adam Ratner, a pediatric infectious disease physician in New York City and the author of Booster Shots, a history of the fight against measles.
"We are in great danger of losing our measles elimination status, if not this year, then almost certainly in the coming years," he says.
Ratner points to kindergarten vaccination rates, which have been falling nationwide for years and are currently at 92.7%. In some communities, vaccination rates are much lower, creating pockets of opportunity for measles to spread. The CDC says a 95% vaccination rate threshold is needed to protect communities against measles outbreaks.
"What we're seeing now is, as vaccine hesitancy has grown, particularly during and after the COVID pandemic, those outbreaks are becoming more frequent and larger," Ratner says.