Effect of Stepwise Perinatal Immunization Education: A Cluster-randomized Controlled Trial

Background: Perinatal immunization education is important for improving the immunization outcomes of infants; however, the content of educational materials used at each perinatal period has not been carefully evaluated. We hypothesized that stepwise education offered at different perinatal periods would improve infant immunization status and enhance maternal immunization knowledge.

Methods: In this cluster-randomized controlled trial, pregnant women were recruited from nine obstetric sites in Niigata, Japan. The intervention group received a stepwise, interactive education intervention (prenatally, postnatally, and 1month after birth). The control group received a leaflet containing general information on immunization. Infant immunization status was evaluated at 6months of age, and maternal immunization knowledge was evaluated by a written survey after each intervention.

Results: Among 188 study participants, 151 (80.3%) replied to the final post-intervention survey. At 6months of age, the percentage of children who completed three doses of inactivated polio, diphtheria, tetanus toxoid, and acellular pertussis (DTaP-IPV) vaccine was higher in the intervention group than in the control (p=0.04); however, no differences between groups were observed for the Haemophilus influenzae type b (Hib) (p=0.67) or 13-valent pneumococcal conjugate (PCV13) vaccines (p=0.20). The duration to the completion of the third dose of the DTaP-IPV, Hib, and PCV13 vaccines was shorter in the intervention group than in the control (p=0.03, p<0.01, and p<0.01, respectively). Furthermore, maternal knowledge scores exhibited significantly greater improvement in the intervention group over time compared with those of the control group (p=0.02).

Conclusions: Stepwise perinatal immunization education improved immunization schedule adherence for required vaccines and improved maternal immunization knowledge.