A new outbreak of meningococcal disease, which causes meningitis, has occurred in recent months in Southern California, mostly among men who have sex with men (MSM). This is the largest outbreak of the disease among MSM to date. Eight percent of those who have contracted the disease have died.

In July, health departments in Los Angeles County, Long Beach, Orange County and San Diego County recommended that all MSM living in or who intend to visit these areas, as well as all HIV-positive MSM statewide, receive the quadrivalent meningococcal conjugate vaccines. This vaccine group protects against serogroup C of meningococcal disease, which is associated with this outbreak. Individuals should receive the vaccine at least two weeks before traveling to the area, the approximate time needed for immunity to develop.

The Centers for Disease Control and Prevention (CDC) reports in its Morbidity and Mortality Weekly Report that between March 4 and August 11, 2016, there have been 25 identified cases of meningococcal disease associated with the Southern California outbreak. Two people (8 percent) have died of the disease.

Clusters of meningococcal disease have emerged among MSM in various major urban areas in the United States and Europe throughout the decade. These cities include New York City between 2010 and 2013, Los Angeles County between 2012 and 2014, Chicago between 2015 and 2016, Berlin between 2012 and 2013 and Paris in 2014. Health departments in these cities recommended vaccination to quell the outbreaks.

Of the 25 individuals identified in the Southern California outbreak, 24 (92 percent) were male and 20 (80 percent) said they were MSM. Forty percent were Latino, which is in line with the local demographics, and the median age was 32, ranging between 17 and 74 years old.

Ten of the identified cases were among residents of Los Angeles County, seven lived in Long Beach, seven lived in Orange County and one lived in another state but had traveled to Los Angeles the week before getting sick. Two of those who contracted the disease were known to have HIV.

For information about the signs and symptoms of meningococcal disease, click here.

To read the CDC report, click here.