State Dependence in Immunization and the Role of Discouragement
We investigate whether having a child immunized at a prior schedule genuinely increases the likelihood of vaccinating the child at the subsequent schedule. Using longitudinal data from the Growing Up in New Zealand study, we apply a random-effects model that also controls for the initial immunization status. We detect sizeable state dependence in immunization, indicated by a significant increase in the likelihood of child immunization by an average of 21 percentage points if the child was immunized at the previous schedule compared to if they were not. However, this effect is exacerbated if a mother is discouraged from having her child immunized during antenatal period.