The U.S. is dealing with the largest outbreak of measles cases since the disease was declared eliminated in 2000, the Centers for Disease Control and Prevention said.
Health authorities as of Wednesday had logged 695 measles cases this year across 22 states, the CDC said in a statement. The announcement confirmed similar findings by CNN that cited data from state and local health departments.
The CDC attributed the 2019 measles surge primarily to the disease being imported into communities with under-vaccinated populations, sparking significantly large outbreaks in Washington state, New York City and New York state.
“The outbreaks in New York City and New York State are among the largest and longest lasting since measles elimination in 2000. The longer these outbreaks continue, the greater the chance measles will again get a sustained foothold in the United States,” the CDC said.
“The longer these outbreaks continue, the greater the chance measles will again get a sustained foothold in the United States.”
Importation involves an unvaccinated traveler visiting a location where there is a measles outbreak and contracting the disease, then returning home and exposing others, the CDC said.
“When measles is imported into a community with a highly vaccinated population, outbreaks either don’t happen or are usually small. However, once measles is in an under-vaccinated community, it becomes difficult to control the spread of the disease,” the CDC said.
Health and Human Services Secretary Alex Azar, in a statement responding to the CDC’s figures, cautioned that measles “is not a harmless childhood illness, but a highly contagious, potentially life-threatening disease.”
“Vaccines are a safe, highly effective public health solution that can prevent this disease,” Azar said. “The measles vaccines are among the most extensively studied medical products we have, and their safety has been firmly established over many years in some of the largest vaccine studies ever undertaken.”
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.
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 had grown to 390. Two pregnant women are among those with 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.
This article has been updated to include the CDC’s announcement.