Increased case-fatality rate associated with outbreaks of Neisseria meningitidis infection, compared with sporadic meningococcal disease, in the United States, 1994-2002.
BACKGROUND
Outbreaks of meningococcal disease are infrequent but important public health events. We characterize outbreak-associated cases in the United States and compare them with sporadic disease.


METHODS
Outbreaks of meningococcal disease that occurred during the period of 1 July 1994 through 30 June 2002 were identified through state health departments, Centers for Disease Control and Prevention records, and a review of newspapers and the medical literature. Cases associated with outbreaks were compared with sporadic cases identified through population-based surveillance.


RESULTS
We identified 69 outbreaks of Neisseria meningitidis infection (median, 9.5 outbreaks per year; range, 3-14 outbreaks per year), which involved 229 patients from 30 states. Forty-three (62%) of the outbreaks involved N. meningitidis serogroup C, 17 (25%) involved serogroup B, and 9 (13%) involved serogroup Y. Twenty-five outbreaks (36%) occurred in communities, and 44 (64%) were organization based, including 12 that occurred in colleges and universities, 19 that occurred in primary and secondary schools, and 8 that occurred in nursing homes. Vaccination campaigns (with the A/C/Y/W-135 meningococcal polysaccharide vaccine) were conducted for 31 outbreaks (28 involving serogroup C and 3 involving serogroup Y). After controlling for age, serogroup, and clinical presentation, outbreak-associated cases were associated with a higher case-fatality rate than were sporadic cases (21% vs. 11%; odds ratio, 3.3; 95% confidence interval, 2.0-5.5).


CONCLUSIONS
Outbreaks remain an important but infrequent public health issue, representing <2% of all cases of meningococcal disease. However, given the increased case-fatality rate found among outbreak-related cases of N. meningitidis infection, additional investigation of factors that favor the transmission and virulence of outbreak-related strains is warranted.
Brooks
Richard
R
Duke University School of Medicine, Durham, North Carolina, USA.
Woods
Christopher W
CW
Benjamin
Daniel K
DK
Rosenstein
Nancy E
NE
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000453:epidemiology / Q000401:mortality*; D008875:Middle Aged; D009026:Mortality; D009345:Neisseria meningitidis; D011159:Population Surveillance; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology