BACKGROUND: Meningococcal disease, caused by the bacteria Neisseria meningitidis,is a severe infection most often characterized by meningitis and septicemia. Rates of meningococcal disease in the United States have been declining since 2000, and are currently at a historic low. Because of the seriousness of meningococcal disease and need for prompt public health follow-up for all cases, completeness of meningococcal disease reporting is presumed to be high. However, questions regarding the completeness of reporting remain. During 2010-2014, approximately 16% of all meningococcal disease cases in the United States were reported from California, making it an ideal place to evaluate the completeness and accuracy of meningococcal disease reporting.
METHODS: We evaluated the completeness and accuracy of meningococcal disease reporting in California from 2010 to 2014 by comparing California inpatient hospital discharge (OSHPD) data to state surveillance data. Hospitalizations with meningococcal ICD-9 codes (036.0-036.9) were identified in the OSPHD database and matched with confirmed and probable meningococcal disease cases in California residents reported to the state surveillance system. Matching was performed using age, birthdate, date of disease onset or hospitalization, hospital discharge date, sex, hospital name, race/ethnicity, and residence (zip code and county). Medical records of cases found in only one of the two databases were reviewed to identify patterns for non-reporting.
RESULTS: Between 2010 and 2014, a total of 486 confirmed meningococcal disease cases were reported to the California state surveillance system. Of these, 442 (90.9%) cases were matched to the OSPHD database. Among the 44 cases identified in the state surveillance system that were not matched to a case in the OSPHD database, 16 (36.4%) died prior to hospitalization, 8 (18.2%) were hospitalized in a federal facility, 11 (25.0%) were not hospitalized, 4 (9.1%) were hospitalized outside of California, and 5 (11.4%) had incomplete hospital discharge data. There were a total of 250 hospitalization records identified in the OSPHD database that did not match with cases in the state surveillance database. Preliminary review of a subset of 15 medical records from unmatched hospitalizations revealed that all but one of the unmatched cases with meningococcal codes in the OSPHD data lacked laboratory results to indicate N. meningitidisinfection, thus were not confirmed cases.
CONCLUSIONS: Accurately characterizing the burden of meningococcal disease in United States is critical for vaccine policy decisions and for monitoring changes in epidemiology. Preliminary analyses suggest that meningococcal disease reporting in California is accurate.