Factors Associated with Pneumococcal Carriage in Healthy Dutch Infants: The Generation R Study

Objective To study the prevalence. risk factors, and dynamics of pneumococcal carriage in infancy. Study design In a population-based prospective cohort study conducted in Rotterdam, the Netherlands between June 2003 in children at age of 1,5, 6, and 14 months. Data on risk factors and November 2006, nasopharyngeal swabs were obtained fro were obtained from midwives, hospital registries, and questionnaires. Results The prevalence of pneumococcal carriage increased from 8.3% at age 1.5 months (n = 627) to 31.3% at age 6 months (n = 832) and 44.5% at age 14 months (n = 757). The prevalence of serotypes covered by the 7-valent conjugate increased from 3.0% to 16.2% and 27.7% at these respective ages. Having siblings (aqjusted odds ratio [aOR] = 4.33; 95% confidence interval [CI] = 1.22 to 15.35) and day care attendance (aOR = 3.05. 95% CI = 1.88 to 4.9.5 at 6 months; aOR = 2.78, 9.5% CI 1. = 70 to 4.55 at 14 months) were associated with pneumococcal carriage. Pneumococcal carriage at age 6 months was associated with pneumococcal carriage at age 1.4 months (aOR = 2.43; 95% CI = 1.50 to 3.94). Pneumococcal carriage was not associated with sex, maternal smoking, maternal educational level, or breast-feeding. Conclusions The prevalence of serotypes covered by the 7-valent conjugate vaccine. p increased in the first year of life. Siblings, day care attendance, and previous pneumococcal carriage were independent factors associated with pneumococcal carriage. (J Pediatr 2008.153:771-6)