The U.S. is dealing with the largest outbreak of measles cases since the disease was eliminated in 2000, according to an analysis by CNN.
As of this week, there have been 681 measles cases across 22 states, the network reported on Wednesday, citing data from state and local health departments.
On Monday, the Centers for Disease Control and Prevention reported 626 cases so far this year. That’s just 41 cases fewer than the 2014 record, which had previously seen the highest number since 2000.
The CDC releases its numbers each Monday using data collected from the previous week. A representative did not immediately respond to a request for comment.
The 22 states reporting cases are Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maryland, Massachusetts, Michigan, Missouri, Nevada, New Hampshire, New Jersey, New York, Oregon, Tennessee, Texas and Washington. This is up from 20 states the previous week and 15 states at the start of this month.
The CDC attributes the rise of measles cases in the country to outbreaks in unvaccinated communities that came into contact with travelers who contracted the disease overseas. Health officials have urged the public to get vaccinated for the disease.
Earlier this month, a public health emergency was declared in New York City by the mayor after a significant rise in cases.
On Monday, the number of measles cases has grown to 390. Two pregnant women are among those who have contracted the disease, the city’s Department of Health and Mental Hygiene said.
The majority of the city’s cases, roughly 83%, have been in Williamsburg, Brooklyn, where Mayor Bill de Blasio ordered mandatory emergency vaccinations. The area’s population includes ultra-Orthodox Jewish communities, some of whom oppose vaccinating their children, the city has said.
Before the measles vaccination program started in 1963, an estimated 3 million to 4 million people contracted measles each year in the U.S. About 400 to 500 of those died, 48,000 were hospitalized and 1,000 developed the brain inflammation encephalitis, the CDC said.
Today, the CDC estimates that 30% of reported measles cases have one or more complications. For every 1,000 reported cases, there’s approximately one case of encephalitis and two to three deaths.