Parental decline of pneumococcal vaccination and risk of pneumococcal related disease in children
Introduction
Immunization is one of the most significant public health achievements of the 20th century [1]. Widespread immunization in the United States has reduced the incidence of polio, smallpox, Haemophilus influenzae type b and measles by greater than 98% [2]. Recent trends, however, suggest that public trust in the national immunization program is eroding [3], [4], [5]. As incidence rates of vaccine-preventable diseases continue to decline, the perceived seriousness of those diseases tends to decrease, and parents are less likely to believe their children are at risk for infection [6], [7], [8]. Public concern, as a consequence, has shifted from disease transmission to vaccine safety, and an increasing number of parents are choosing to either decline or delay immunizations for their children [9], [10].
Deciding not to vaccinate has a negative impact on the health of children and their surrounding communities. Population-based studies have demonstrated that the local risk of vaccine-preventable diseases increases in communities with high rates of children with nonmedical exemptions to school immunization requirements [11], [12]. Studies using individual-level data have shown that children of parents who declined immunizations were approximately 23-times more likely to acquire pertussis and 9-times more likely to contract varicella than vaccinated children [13], [14].
Pneumococcal disease is a serious vaccine-preventable disease that is still endemic in the United States. Before the introduction of the seven-valent pneumococcal conjugate vaccine (PCV7) in 2000, an estimated 17,000 cases of invasive pneumoccocal disease occurred annually among children younger than 5 years [15]. Since routine use of PCV7, rates of invasive pneumococcal disease and pneumonia hospitalizations in children have decreased by 17–77% [16], [17], [18], [19]. The disease risks associated with the parental choice to decline PCV7 vaccination are currently not known. We examined the association between the parental decision to decline PCV7 vaccinations and the risk of hospitalization due to invasive pneumococcal disease or lobar pneumonia in children.
Section snippets
Setting and study cohort
We conducted a case–control study nested within a cohort of children enrolled in the Kaiser Permanente Colorado (KPCO) health plan, a Denver-based plan with more than 430,000 members. KPCO provides its members with full coverage for all pediatric vaccines as recommended by the Advisory Committee on Immunization Practices [20]. Immunization records are captured in the KPCO electronic medical record, which also includes data from the KPCO immunization registry and Colorado state immunization
Study cohort and cases
We assembled a cohort of 50,857 children ages 2 months to 5 years, who were born after 1999, and continuously enrolled in KPCO for a minimum of 6 months between October 2004 and September 2009. In this cohort, we identified 803 patients hospitalized with an ICD-9 diagnostic code for a potential pneumococcal-related illness in the clinical databases. We excluded 690 children (86%) for conditions other than lobar pneumonia, pneumococcal meningitis, pneumococcal sepsis, and pneumococcal
Discussion
We report an apparent association between the parental decision to decline pneumococcal immunization and the risk of hospitalization due to invasive pneumococcal disease or lobar pneumonia in children. Children of parents who declined pneumococcal vaccination were 6.5 times more likely to be hospitalized for clinically defined pneumococcal disease than vaccinated children; the association was 10-fold in children without asthma.
PCV7 vaccination of young children is highly efficacious against
Acknowledgements
The study was supported in part by the Kaiser Permanente Colorado Institute for Health Research.
Jason Glanz is supported in part by a career development grant from the National Institute of Allergy and Infectious Diseases (K01 AI073295).
We thank Candido Chacon for his role in data collection and medical record review.
The findings and conclusions expressed in this article are those of the authors and do not necessarily represent the official views of Kaiser Permanente Colorado, the National
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