title: Can herd immunity influence the assessment of vaccine efficacy in nonrandomized studies?
authors.forename: K
authors.initials: K
authors.lastname: Mühlemann
authors.forename: N S
authors.initials: NS
authors.lastname: Weiss
mesh_terms: D015982:Bias; D016000:Cluster Analysis; D006801:Humans; D007110:Immunity, Active; D007239:Infections / Q000453:epidemiology*; D015203:Reproducibility of Results; D012107:Research Design; D014612:Vaccines / Q000276:immunology*
chemical_list: D014612:Vaccines