Acquisition of Streptococcus pneumoniae and nonspecific morbidity in infants and their families - A cohort study

Background: Most children are believed to acquire Streptococcus pneunioniae asymptomatically, with only a few developing overt S. pneunioniae disease. This study investigates the relationship between acquisition of S. pneumoniae and mild nonspecific infection leading to general practitioner (GP) consultation. Methods: A prospective birth cohort study of 213 infants assessed at home 9 times during 24 weeks by nasopharyngeal swab and parental interview was conducted. Results: All positive S. pneunioniae swabs (including acquisition and carriage) were significantly associated with GP consultations for infection by the study infant compared with infants with negative swabs [odds ratio (OR), 1.6; 95% confidence interval (CI) 1.1-2.2; P = 0.005]. There was a stronger association with. pneumoniac acquisition alone (OR 2.1 ; 95% Cl 1.3-3.4; P = 0.00 1) than with (OR 1.4; 95% CI 0.9-2.0; P = 0.1). Multivariate analysis confirmed that S. pneumoniae acquisition by the study subject was independently associated with GP consultations: adpasted hazard ratio, 1.8 (95% CI 1.1-2.9); P = 0.02., A similar and independent association was found between S. pneumoniae acquisition by the study subject, and GP consultations for infection by the family (adjusted hazard ratio, 1.8; 95% CI 1.1-2.8; P = 0.01). Conclusion: Acquisition of S. pneumoniae by the study infant was significantly associated with GP consultations for infection by the infant or family.