(CNN) – The measles outbreak across the United States continues to grow.
The Centers for Disease Control says it has now identified 1,077 cases across 28 states.
That’s an increase of 33 cases from last week.
This marks the greatest number of measles cases reported in the United States since 1992.
The Centers for Disease Control and Prevention says measles can be prevented with the MMR vaccine, calling it “very safe and effective.”
Two doses of MMR vaccine are about 97-percent effective at preventing measles; one dose is about 93-percent effective.