Background: Meningococcal disease is a rare but serious bacterial infection. Three clusters among men who have sex with men (MSM) have been reported in the U.S. since 2012. We characterized the risk of disease among MSM to inform discussions regarding the use of meningococcal vaccines in this population
Methods: All meningococcal cases among males aged 18-64 years reported to the National Notifiable Disease Surveillance System between January 2012 and June 2015 were reviewed. MSM status and risk factors for disease were collected from state health departments. We compared annualized incidence rates among MSM and men not known to be MSM (non-MSM). Denominators were estimated using 2012 census data and published estimates of the proportion of MSM in the U.S. Isolates were characterized using standard microbiological methods and PCR; genetic similarity of these isolates was assessed using pulsed-field gel electrophoresis (PFGE) and whole genome sequencing (WGS).
Results: Seventy-four cases of meningococcal disease were reported among MSM and 453 among non-MSM. The risk in MSM was 4.0 times (95% CI: 3.55-4.50) the risk in non-MSM. HIV-infected MSM had 10.1 times (95% CI: 6.1-16.6) the risk of HIV-uninfected MSM. Among MSM with known information, 48.1% (25/52) reported recreational drug use, 31.7% (20/63) tobacco use, and 45.2% (14/31) multiple or anonymous sexual partners. Sixty-two cases (83.8%) among MSM were due to serogroup C N. meningitidis (NmC), compared to 98 (21.6%) among non-MSM. PFGE and WGS revealed distinct phylogenetic groups associated with the MSM clusters.
Conclusions: MSM, particularly HIV-infected MSM, are at higher risk for meningococcal disease than non-MSM in the U.S. While vaccination of MSM may reduce their risk, policymakers should consider other factors, including suboptimal vaccine immune response in HIV-infected persons, low absolute risk of disease, and likely need for booster doses in vaccinated MSM when making recommendations.