The number of measles cases in the United States reached a record-setting 704 for the year last week, the greatest number of cases in 25 years, health officials said Monday.

The Centers for Disease Control and Prevention said that as of April 29, 704 measles cases have been confirmed in 22 US states since the start of the year.

That was a jump of 78 cases from the previous week, it said.

Measles were declared eliminated in the US in 2000 but this year has seen the greatest number of confirmed cases since 1994.

Three percent of the measles cases developed pneumonia, while nine percent were serious enough to require hospitalization, said CDC director Robert Redfield.

“At this time, there has been no death,” Redfield said.

There were 17 measles outbreaks in 2018, but most of the cases were from outbreaks in New York state, New York City, and New Jersey — mainly among unvaccinated members of Orthodox Jewish communities, the CDC said.

Read also:

“Families are being targeted with inaccurate and misleading information about vaccines,” said Nancy Messonnier, head of the CDC’s National Center for Immunization and Respiratory Diseases.

Federal health officials are struggling to counter disinformation spread by groups opposed to vaccinations.

“We know vaccines are safe because they are among the most studied medical products we have,” said Health and Human Services Secretary Alex Azar.

The vast majority of measles cases “involve children who have not been vaccinated,” Azar said.

According to the CDC, 94 percent of children entering kindergarten in the United States in 2017 had received their two doses of the MMR vaccine to protect them from mumps, measles and rubella.

However the rate of vaccination is lower in certain communities such as the Orthodox Jews in the New York area, where the epidemic continues, and the Russian-speaking community in Washington state, where the epidemic was declared over last week.