Over 40 people in Los Angeles County and surrounding areas have been infected with mumps, according to the Los Angeles Department of Public Health.
"The majority of these cases are among MSM but some are women and heterosexual men with social connections to MSM cases," the department said, using an acronym to describe men who have sex with men.
Mumps is "highly infectious" and is transmitted through saliva, according to the department; behaviors that involve the exchange of saliva, such as kissing or sharing utensils, cups lipstick or cigarettes can increase the spread of the virus.
Symptoms can include a few day of fever and fatigue, deafness and salivary gland swelling and pain, the department said. Complications can include orchitis, which is inflammation of the testicles.
Most cases of transmission have occurred at large venues, like athletic clubs, bars, theaters and nightclubs, the department said. Most people infected have not been completely vaccinated, though some were fully vaccinated, according to the department.
The department recommends people get completely vaccinated. People who might be infected should wear a mask and stay between 3 to 6 feet from other patients, the department said. They should also stay home and avoid public spaces for five days after their salivary glands begin to swell or until other symptoms clear.