Decline in Early Childhood Respiratory Tract Infections in the Norwegian Mother and Child Cohort Study After Introduction of Pneumococcal Conjugate Vaccination

Department of Chronic Diseases, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway.
The Pediatric Infectious Disease Journal (Impact Factor: 2.72). 05/2012; 31(9):951-5. DOI: 10.1097/INF.0b013e31825d2f76
Source: PubMed


The 7-valent pneumococcal conjugate vaccine (PCV7) was introduced into the Norwegian Childhood Immunization Program in 2006. A substantial effectiveness of PCV7 immunization against invasive pneumococcal disease has been demonstrated, whereas evidence of its impact on respiratory tract infections are less consistent.
This study included children participating in the Norwegian Mother and Child Cohort Study, which recruited pregnant women between 1999 and 2008. Maternal report of acute otitis media (AOM), lower respiratory tract infections (LRTIs) and asthma in the child was compared by PCV7 immunization status, as obtained from the Norwegian Immunization Registry. Generalized linear models with the log-link function were used to report adjusted relative risks (RRs) and 95% confidence intervals (CIs).
For children who had received 3 or more PCV7 immunizations by 12 months of age, the adjusted RRs of AOM and LRTIs between 12 and 18 months were 0.86 (95% CI: 0.81, 0.91) and 0.78 (95% CI: 0.70, 0.87) respectively, when compared with nonimmunized children. A reduced risk of AOM, RR 0.92 (95% CI: 0.90, 0.94), and LRTIs, RR 0.75 (95% CI: 0.71, 0.80), between 18 and 36 months of age was also identified among children who had received 3 or more immunizations by 18 months of age. No association was seen between PCV7 immunization and asthma at 36 months of age.
Reduced incidences of AOM and LRTIs before 36 months of age were observed among children immunized with PCV7 through the childhood immunization program.

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    • "The incidence of IPD declined both in the age group targeted for vaccination as well as in other age groups (as an indirect effect; [3] [4] [5] [6] [7] [8]). Furthermore, the occurrence of acute otitis media and lower respiratory tract infections reduced in children [9], and nasopharyngeal carriage of vaccine serotypes (VT) declined [6,10–12]. Concurrently, an increased incidence of IPD caused by non-vaccine serotypes (NVT; serotype replacement) following PCV7 introduction has consistently been observed in different settings [6] [13] [14]. "
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