Los Angeles County health officials on Wednesday announced a new local outbreak of measles among five people after four residents were exposed to an international visitor who had not been immunized from the virus.

Authorities did not elaborate on the international visitor or any of the infected.

Those exposed visited more than 30 locations primarily in Los Angeles’ westside and in the South Bay area between Jan. 26 and Feb. 1, officials said.

The locations include a Starbucks at 11707 San Vicente Blvd. in Brentwood, a Whole Foods store at 11737 San Vicente Blvd. in Brentwood and a Pinkberry Yogurt at 1612 Montana Avenue in Santa Monica.

A full list of locations visited by the confirmed cases can be found here.

Health officials warned that unvaccinated people or those with an unknown immunization status who visited the sites at the same dates and times are at risk of developing measles from seven to 21 days after being exposed.

People who were in the locations at the same time are advised to review their immunization and medical records to ensure they are protected against measles, and contact and notify their health care provider as soon as possible about a potential exposure. They should also monitor themselves for the illness.

Symptoms include fever and/or an unexplained rash from seven days to 21 days after exposure, cough, runny nose and red, watery eyes, officials said.

Children under 5, adults older than 20, pregnant women and people with weakened immune systems are especially vulnerable to serious complications that include pneumonia and encephalitis, according to the U.S. Centers for Disease Control and Prevention. More common complications include diarrhea and ear infections that can lead to permanent hearing loss in children.

In 2019, 20 L.A. County residents contracted measles, in addition to 14 cases among people visiting the region, according to authorities.