(CNN)This year, Washington state is averaging more than one new measles case a day as officials try to stop the disease's spread.
Since January 1, Clark County Public Health has confirmed 49 cases of measles. In King County, home of Seattle, at least one confirmed case was reported.
A vast majority of those who came down with measles -- 41 -- were not vaccinated against the disease, Clark County officials said. One patient received a vaccination against MMR (measles, mumps and rubella), but the health agency declined to provide more details on that case "to protect the patient's privacy."
Most of the Washingtonians affected -- 34 -- are children between the ages of 1 and 10.
"Clark County Public Health is urging anyone who has been exposed at an identified location and believes they have symptoms of measles to call their health care provider prior to visiting the medical office to make a plan that avoids exposing others in the waiting room," the agency said.
Washington isn't the only state grappling with the disease. Officials in Harris County, Texas, which includes Houston, reported three cases of measles Monday, bringing the total number of cases in the state this year to six.
According to the US Centers for Disease Control and Prevention, at least 10 states have reported cases of measles in 2019: California, Colorado, Connecticut, Georgia, Illinois, New Jersey, New York, Oregon, Texas and Washington.
In all, at least 79 cases have been reported nationwide this year.
Two other outbreaks have also been reported this year, the CDC said, in New York state and New York City. Health officials have said those outbreaks are within observant Jewish communities.
According to the New York State Department of Health, at least 209 cases have been reported there since October: 64 in Brooklyn and 145 in Orange and Rockland counties as of last week.
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The outbreaks began when travelers to Israel and Ukraine returned with the illness. There are large measles outbreaks ongoing in both of those countries.
"In a given year, more measles cases can occur for any of the following reasons: an increase in the number of travelers who get measles abroad and bring it into the U.S. and/or further spread of measles in U.S. communities with pockets of unvaccinated people," the CDC website says.
The measles vaccine -- known as the MMR vaccine -- is very effective. One dose is about 93% effective at preventing measles if you come in contact with the virus. Two doses are about 97% effective.
Experts recommend that children receive the vaccine in two doses: the first between the ages of 12 months and 15 months and the second between 4 and 6 years old.
