Evaluation of the Indirect Effects of a Pneumococcal Vaccine in a Community-Randomized Study

• Published in: Journal of biopharmaceutical statistics Vol. 16; no. 4; pp. 453 - 462
• Main Authors: Moulton, L. H., O'Brien, K. L., Reid, R., Weatherholtz, R., Santosham, M., Siber, G. R.
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis Group 01.08.2006
• Subjects: Child, Preschool; Community-randomized trial; Heptavalent Pneumococcal Conjugate Vaccine; Humans; Indirect effects; Infant; Logistic Models; Meningococcal Vaccines - immunology; Meningococcal Vaccines - therapeutic use; Pneumococcal Infections - epidemiology; Pneumococcal Infections - immunology; Pneumococcal Infections - prevention & control; Pneumococcal vaccine; Pneumococcal Vaccines - immunology; Pneumococcal Vaccines - therapeutic use; Streptococcus pneumoniae; United States; United States Indian Health Service; Vaccines, Conjugate - immunology; Vaccines, Conjugate - therapeutic use; United States
• ISSN: 1054-3406; 1520-5711
• DOI: 10.1080/10543400600719343

When a sufficiently high proportion of a population is immunized with a vaccine, reduction in secondary transmission of disease can confer significant protection to unimmunized population members. We propose a straightforward method to estimate the degree of this indirect effect of vaccination in the context of a community-randomized vaccine trial. A conditional logistic regression model that accounts for within-randomization unit correlation over time is described, which models risk of disease as a function of community-level covariates. The approach is applied to an example data set from a pneumococcal conjugate vaccine study, with study arm and immunization levels forming the covariates of interest for the investigation of indirect effects.