DTP vaccination and child survival in observational studies with incomplete vaccination data.

摘要: BACKGROUND: Observational studies of diphtheria-tetanus-pertussis (DTP) vaccine from longitudinal study sites have reported divergent effects on child survival, ranging 10-fold reduction to threefold increased mortality. None these had complete information DTP vaccinations both survivors and children who died. We reviewed the data analysis methodology assess whether methodological differences could explain results. DESIGN: Studies used case-control design, survival with interval-fixed vaccination status (landmark approach), retrospective updating status. RESULTS: Seven using a design or landmark approach found negative effect survival. Eight nine analyses beneficial effect. This length interval between collection visits. long visits very high mortality rates among unvaccinated children, low rate ratios for vaccinated compared strongly estimates DTP. CONCLUSION: The results in observational impact are partly because differences. To routine vaccinations, designs which minimize bias warranted. Randomized trials should be considered.