LOS ANGELES — Los Angeles County reported another measles case involving a resident or traveler this week, prompting officials to renew their call for all residents to make sure they are up to date on their vaccinations.

The latest case — the fourth so far this year — involves a visitor who recently arrived in L.A. County from another country, according to the county Department of Public Health.

The measles patient was not infectious while traveling, health officials said, but some people may have been exposed to the virus in healthcare facilities. Officials did not identify the specific sites but said the healthcare facilities are directly contacting potentially exposed patients and employees.

Measles is one of the most contagious diseases, and it can spread easily on surfaces and in the air — remaining infectious for hours, even after a sickened person has left the room.

Symptoms of measles include a high fever above 101 degrees, cough, runny nose, red and watery eyes and a rash, which usually starts on the face and spreads to the rest of the body.

"As L.A. County residents begin to travel this summer, and with measles cases increasing among those who have recently traveled, we remind everyone that the best way to protect yourself and your family from infection is with the highly effective measles vaccine," Dr. Muntu Davis, the county health officer, said in a statement Tuesday.

Health officials generally recommend babies get their first measles vaccination when they're 12 to 15 months old, followed by a second dose between 4 and 6 years old.

But infants as young as 6 months old should get a measles vaccine before traveling internationally, and then should get two more doses after their first birthday, according to the U.S. Centers for Disease Control and Prevention.

Having two doses of the measles vaccine is 97% effective against infection, health officials say.

Measles vaccination is required as a condition of entry for schools in California and, at age 1, at child-care centers — though children can receive a medical exemption. State law allows parents to skip immunizations for children who are enrolled in independent study programs and do not receive classroom-based instruction.

Before a vaccine for measles became available in 1963, the disease resulted in an estimated 400 to 500 deaths a year, as well as 48,000 hospitalizations — with 1,000 people suffering brain swelling, the CDC says.

Two L.A. County residents have tested positive for measles this year — one who had recently returned from Texas, which is in the midst of a deadly measles outbreak, and another who had flown back from Taiwan. A non-L.A. County resident also tested positive after arriving on a flight from South Korea.

The U.S. is in the midst of one of its worst years for measles in the last generation, with 935 cases already reported nationally this year, CDC data show. About 38% of patients are age 5 through 19, and 30% are age 4 and younger.

Of those with confirmed measles infection, 96% either are unvaccinated or have an unknown vaccination status, according to the CDC.

The latest measles case count is already the second-highest in 25 years, eclipsed only by the 1,274 cases reported in all of 2019.

Three confirmed measles deaths have been reported — two among unvaccinated school-age children in Texas who had no underlying medical conditions, and one in an unvaccinated adult in New Mexico, according to the CDC's Morbidity and Mortality Weekly Report.

L.A. County officials suggest residents contact their healthcare provider as soon as possible about a possible measles exposure if they are pregnant or have a weakened immune system — regardless of their immunization history. Healthcare providers should also be contacted if the exposed person is an infant or is unvaccinated.

"If symptoms develop, stay at home, and avoid school, work and any large gatherings," the county said in a statement. "Do not enter a healthcare facility before calling them and making them aware of your measles exposure and symptoms."

People can spread measles to others from four days before the disease's telltale rash appears through four days afterward, according to the CDC. People who have not been immunized against measles, either through vaccination or prior infection, are at risk of getting sick between seven and 21 days after exposure.

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