The number of measles cases in the United States this year has reached 1,001, health officials said on Wednesday, as they vowed to stop the spread of misinformation about vaccines.
The announcement comes days after authorities declared the US was in danger of losing its "elimination status" on the contagious respiratory disease if the current outbreaks continue.
"The 1,000th case of a preventable disease like measles is a troubling reminder of how important" it is to ensure that people understand that vaccines are safe, Health and Human Services (HHS) Secretary Alex Azar said in a statement.
Azar vowed to "continue our efforts to support local health departments and health care providers in responding to this situation, with the ultimate goal of stopping the outbreak and the spread of misinformation about vaccines."
"We cannot say this enough: Vaccines are a safe and highly effective public health tool that can prevent this disease and end the current outbreak."
The previous record number of cases came in 1992 when 963 cases were reported across the year -- a figure now surpassed in less than the first six months of 2019.
The Centers for Disease Control and Prevention (CDC) were giving health care providers guidelines for recognizing and preventing measles, and developing a toolkit for physicians to counter misinformation, Azar said.
Authorities declared measles eliminated in the US in 2000, a goal set in 1966 with the introduction of the vaccine.
Measles is considered eliminated when there is an absence of continuous disease transmission for 12 months or more in a specific geographic area, according to the CDC.
An ongoing outbreak in and around New York that started last fall is threatening the nation's "elimination status" -- if it continues for four more months, the country will no longer be able to say it has eliminated measles.
Even though New York city officials began requiring residents in heavily affected areas, many with large Orthodox Jewish communities, to be vaccinated starting in April, the city still had 173 cases that month and 60 in May.
The US has never counted zero measles cases.
Since 2000, the number has fluctuated between a few dozen and a few hundred cases per year, with 667 cases recorded during a 2014 outbreak in Ohio, especially in Amish communities.
The disease's resurgence can mostly be traced back to un- or under-vaccinated travellers who brought the infection back with them from abroad -- that's what happened last year when cases were reported throughout the country, originating from the Philippines, Israel and Ukraine.