Objectives: To determine whether low birth weight (LBW) children are at greater risk of reported pertussis and complications of pertussis in the first 2 years of life than are normal birth weight (NBW) children.
Study design: We performed a secondary analysis of three data sets containing statewide information among Wisconsin residents for children born between January 1, 1981, and December 31, 1990. We identified all reported cases of pertussis among children younger than 2 years of age and linked this information with birth certificate data and hospitalization data to determine the relative risk of reported pertussis in LBW compared with NBW children. We also compared the frequency of reported complications of pertussis in LBW and NBW children.
Results: We analyzed reports of 549 pertussis cases; 49 cases occurred in LBW children. The LBW children were significantly more likely to have reported pertussis than were NBW children (relative risk 1.86; 95% confidence interval 1.33, 2.38). The rates of pneumonia and seizures did not differ among LBW and NBW children; however, LBW children with reported pertussis were significantly more likely to be hospitalized than were NBW children (relative risk 1.40; 95% confidence interval 1.11, 1.69).
Conclusion: In addition to timely vaccination of all infants, efforts are needed to determine additional ways to reduce the risk of pertussis among LBW infants and children.