(CNN) - Measles cases in the U.S. now stands at 1,044 in 28 states.
The Centers for Disease Control reported the latest count as of Friday. This marks the largest number reported in the U.S. since 1992.
Symptoms include runny nose, red eyes, a cough, high fever and the telltale rash.
Serious complications include pneumonia and inflammation of the brain.
The CDC said that measles outbreaks start when people bring get infected from traveling abroad and spread it further among pockets of unvaccinated people.
The best preventative action is to get the MMR vaccine that protects against measles, mumps and rubella.
New York, one of the states with an outbreak, responded last week by eliminating the religious exemption for mandatory vaccinations.