Outbreak of Serogroup C Meningococcal Disease Primarily Affecting Men Who Have Sex with Men - Southern California, 2016

During March 4-Aug 11, 2016, 25 outbreak-associated cases of meningococcal disease, including two deaths (8% case-fatality ratio), were reported in Southern California. Twenty-four of the cases were caused by serogroup C Neisseria meningitidis (NmC) and one by N. meningitidis with an undetermined serogroup (Figure). On June 24, 2016, in response to this increase in NmC cases, primarily among men who have sex with men (MSM) in Los Angeles County, the city of Long Beach, and Orange County, the California Department of Public Health (CDPH) issued a press release and health advisory, declaring an outbreak of NmC in Southern California. Increased awareness of the signs and symptoms of meningococcal disease (http://www.cdc.gov/meningococcal/ about/symptoms.html) and prompt early case recognition among health care providers are critical. During investigations of meningococcal disease caused by any serogroup, health departments are encouraged to assess HIV status of all patients and sex of sex partners in cases occurring among males aged ≥16 years.