Increased attack rate of meningococcal disease in children with a pregnant mother.

OBJECTIVE To investigate the relationship between meningococcal disease and family composition, especially pregnancy in mothers. METHODS This was a retrospective matched case-control study. Case patients were children (aged 0-18 years) who had meningococcal disease and were admitted to our hospital from 1990 to 2002. Children who were admitted to 1 of the general pediatric wards of the hospital during the same period and did not have meningococcal disease served as control subjects. One control subject (matched according to gender, age, and year, and season of admission) was enrolled for each case patient. Parents of case patients and control subjects were asked to fill out a questionnaire on family composition, birth dates of siblings, and pregnancy at the time of hospital admission. RESULTS A total of 88 matched case-control pairs were included. In the case group, 17 (19%) mothers reported having been pregnant at the time of hospitalization of their child, compared with 2 (2%) in the control group. Other family characteristics were not different. After adjustment for confounding factors, pregnancy of mothers remained a significant risk factor for meningococcal disease in children (odds ratio: 11.7; 95% confidence interval: 2.6-53.9). CONCLUSIONS Meningococcal disease in children was highly associated with pregnancy of the patient's mother during hospitalization. Mechanisms by which the presence of a pregnant mother in a family affects the attack rate of meningococcal disease in her children need additional investigation.