This was the week the CDC started to push back against the insanely self-destructive anti-vaccination movement.

A top official at the Centers for Disease Control and Prevention (CDC) on Thursday said the country’s anti-vaccine movement has been a major factor in this year’s measles outbreak, a trend that she called “frustrating.”

“This is not a problem of the measles vaccine not working. This is a problem of the measles vaccine not being used,” Anne Schuchat, the head of the National Center for Immunization and Respiratory Diseases, said in a briefing with reporters Thursday.

The briefing was the first time that the CDC has spoken publicly about the measles outbreak that has erupted over the last month, with most cases stemming from the Disneyland theme park in California. …

The U.S. saw a record 644 cases in 2014, the highest number since the disease was officially eliminated in 2000. Before then, the CDC rarely saw more than 60 cases in one year.

“This is a wake-up call to make sure we prevent measles from gaining a foothold in our country,” she warned. “It’s only January, and we’ve already had 84 cases.”