title: Epidemiological studies of the non-specific effects of vaccines: II--methodological issues in the design and analysis of cohort studies.
abstract: We review sources of bias which can affect non-randomized cohort studies of non-specific effects of vaccines on child mortality. Using examples from the literature on non-specific effects, we describe different sources of selection and information bias, and, where possible, outline analysis strategies to mitigate or eliminate such biases.
authors.affiliation: Department of Mathematics and Statistics, The Open University, Milton Keynes, UK. c.p.farrington@open.ac.uk
authors.forename: C P
authors.initials: CP
authors.lastname: Farrington
authors.forename: M J
authors.initials: MJ
authors.lastname: Firth
authors.forename: L H
authors.initials: LH
authors.lastname: Moulton
authors.forename: H
authors.initials: H
authors.lastname: Ravn
authors.forename: P K
authors.initials: PK
authors.lastname: Andersen
authors.forename: S
authors.initials: S
authors.lastname: Evans
mesh_terms: D015982:Bias; D002675:Child, Preschool; D015331:Cohort Studies; D005568:Forms and Records Control; D006801:Humans; D007223:Infant; D008499:Medical Records; D014611:Vaccination / Q000401:mortality*; D014612:Vaccines / Q000009:adverse effects
chemical_list: D014612:Vaccines