Impact of a multi-component antenatal vaccine promotion package on improving knowledge, attitudes and beliefs about influenza and Tdap vaccination during pregnancy

Objective: Understanding whether interventions designed to improve antenatal vaccine uptake also change women's knowledge about vaccination is critical for improving vaccine coverage. This exploratory study evaluates the effectiveness of a multi-component influenza and tetanus, diphtheria, and acellular pertussis (Tdap) vaccine promotion package on improving women's knowledge, attitudes and beliefs toward antenatal vaccination. Study Design: In 2012/2013 a cluster-randomized trial was conducted to test the effectiveness of a vaccine promotion package on improving antenatal vaccine coverage. Participants included 325 unvaccinated pregnant women from 11 obstetric practices in Georgia. Eleven health beliefs measures were assessed at baseline and 2-3months post-partum. Outcomes were differences in proportions of women citing favorable responses to each measure between study groups at follow-up. Results: Women enrolled in their third trimester had a higher probability of asking family members to vaccinate to protect the infant if they were in the intervention group versus the control group (36% vs. 22%; risk ratio [RR] = 1.65, 95% confidence interval [CI]: 1.21, 2.26). A similar association was not observed among women enrolled before their third trimester (39% vs. 44%; RR = 0.93, 95% CI: 0.50, 1.73). There were no other significant differences at follow-up between study groups. Conclusions: While exposure to the intervention package may have raised awareness that vaccinating close contacts can protect an infant, there is little evidence that the package changed women's attitudes and beliefs toward antenatal vaccination. Future research should ensure adequate exposure to the intervention and consider study design aspects including power to assess changes in secondary outcomes, discriminatory power of response options, and social desirability bias. This study is registered with clinicaltrials.gov, study ID NCT01761799.