The U.S. has broken a decades-old record for the most measles cases reported in a single year, with 971 cases reported so far in 2019, officials announced Thursday.

The Centers for Disease Control and Prevention (CDC) said the total number of cases through the first five months of this year has surpassed the record 963 cases reported for all of 1994.

“Measles is preventable and the way to end this outbreak is to ensure that all children and adults who can get vaccinated, do get vaccinated,” CDC Director Robert Redfield said in a statement. ADVERTISEMENT

Measles is extremely contagious. The majority of measles outbreaks this year have spread through communities where parents have decided not to vaccinate their children.

CDC officials encouraged parents with questions about measles vaccines to consult with their child’s pediatrician. Concerns based on misinformation about the vaccine's safety and effectiveness, as well as disease severity, may lead parents to delay or refuse vaccines, the agency said.

“Again, I want to reassure parents that vaccines are safe, they do not cause autism. The greater danger is the disease that vaccination prevents,” Redfield said.

Measles was declared eliminated in 2000, but this year’s outbreaks have been worsened by anti-vaccine groups that spread misinformation among vulnerable groups.

Most of the measles cases are concentrated in New York, where two outbreaks have been raging in Rockland County as well as in Brooklyn and Queens. Most of these cases have involved members of the Orthodox Jewish community.

The outbreak prompted New York City Mayor Bill de Blasio Bill de BlasioOVERNIGHT ENERGY: California seeks to sell only electric cars by 2035 | EPA threatens to close New York City office after Trump threats to 'anarchist' cities | House energy package sparks criticism from left and right EPA threatens to close New York City office after Trump threats to 'anarchist' cities New Year's Eve in Times Square to be largely virtual amid pandemic MORE (D) and public health officials to declare a health emergency, and mandate that families get children vaccinated against measles or pay a $1,000 fine.

Between September and May 29, there have been 550 confirmed cases in New York City. As of May 28, there were 254 confirmed cases of measles in Rockland County.

Those outbreaks have continued unabated for nearly seven months. If they continue through summer and fall, CDC officials said the U.S. may lose its measles elimination status.

“That loss would be a huge blow for the nation and erase the hard work done by all levels of public health,” the agency said in a statement.

Before widespread use of the measles vaccine, an estimated 3 to 4 million people got measles each year in the United States, along with an estimated 400 to 500 deaths and 48,000 hospitalizations, the CDC said.

Measles is largely preventable with the measles, mumps and rubella vaccine, but there is no cure.