BACKGROUND: Between January and March 2016, five cases of meningococcal disease were reported among adults experiencing homelessness in Boston. Reports of meningococcal disease in this population are rare. We aimed to evaluate factors contributing to increased risk for meningococcal disease among adults experiencing homelessness in Boston.
METHODS: We conducted a matched case-control evaluation. A case was defined as laboratory-confirmed Neisseria meningitidis with illness onset on or after May 1, 2015, in an adult experiencing homelessness in the Boston-metro area. Five controls were matched to each case by sex, age-group, and use of the same emergency shelter facility during the case’s infectious period. Participants were interviewed and their medical records reviewed to identify risk factors. Univariate conditional logistic regression was used to calculate exact matched odds ratios (eMOR) and 95% confidence intervals (CI).
RESULTS: Five cases and 25 controls were enrolled. Compared to controls, a higher proportion of cases were black (80% vs. 44%) or experienced homelessness for less than one year (60% vs. 32%). During the infectious period, a higher proportion of cases had >1 kissing partner (60% vs. 32%) or slept in an emergency shelter room with ≥50 people (40% vs. 20%). None of these differences were statistically significant. The only factor significantly associated with disease was history of any immunosuppressive condition (HIV, lupus, or diabetes) (eMOR: 10.57; 95% CI: 1.79–∞; p = 0.02).
CONCLUSIONS: While history of immunosuppressive condition was significantly associated with meningococcal disease among adults experiencing homelessness, other typical risk factors such as crowding and kissing multiple partners were not. Sample size limited this analysis; enhancing meningococcal disease surveillance by collecting homeless status will allow for more robust evaluation.