Decline in early childhood respiratory tract infections in the norwegian mother and child cohort study after introduction of pneumococcal conjugate vaccinationArchived

ECDC comment

The findings of this population-wide study, describing a declining incidence of respiratory tract infections by year of birth after the implementation of PCV7, confirm the efficacy of PCV7 vaccination in the prevention of AOM and pneumonia that has been shown by earlier randomised controlled trials.

Magnus MC, Vestrheim DF, Nystad W, Håberg SE, Stigum H, London SJ, Bergsaker MA, Caugant DA, Aaberge IS, Nafstad P. Pediatr Infect Dis J. 2012 Sep;31(9):951-5.

The findings of this population-wide study, describing a declining incidence of respiratory tract infections by year of birth after the implementation of PCV7, confirm the efficacy of PCV7 vaccination in the prevention of AOM and pneumonia that has been shown by earlier randomised controlled trials. The study design and analysis controlled for influence of potentially confounding trends, such as improvement of day-care carriage and decreasing prevalence of smoking during the study period. The inclusion of asthma in the outcome markers was worth of, given that an earlier trial from South Africa had reported an increase in hospital admissions due to asthma symptoms among children immunized with a 9-valent PCV (Klugman KP, et al. N Engl J Med 2003;349:1341). Limitations of the study included potential misclassification through maternal report and selection bias, given that children with follow-up information of up to 36 months might well constitute a distinct group of the cohort.