Evaluation of Two Vaccine Education Interventions to Improve Pertussis Vaccination among Pregnant African American Women: A Randomized Controlled Trial

Immunisation with tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine of mothers and others with infant contact is a strategy to protect young infants from pertussis, yet maternal Tdap vaccination in the United States (US) remains low. This evaluation of communication strategies to increase maternal pertussis vaccination is designed to fill an evidence gap for rigorously evaluated interventions for increasing vaccine acceptance among this population. In particular, as it was conducted among pregnant African American women in particular, the study may have implications for minority women for whom distrust, a lack of information, and fear of vaccination may result in lower vaccination rates compared with other population groups.

Tailored messaging based on the Elaboration Likelihood Model (ELM) framework involves two types of information processing: central and peripheral. "Central processing is evoked when an individual has the motivation and ability to analyze a message that is information-based and personally relevant; central processing tends to occur for decisions that are higher-risk, and result in stronger and less modifiable behavioral changes. In contrast, peripheral processing is evoked when simplistic messages or peripheral cues (e.g., brand logos) are used; peripheral processing tends to result in behavioral changes that are more subject to change and less enduring....Given that in the context of vaccination a more enduring change in attitude is required, educational messages that utilize the central route may be more appropriate. However, it is unclear how these messages can be effectively delivered."

This study was a prospective, randomised controlled trial (RCT) designed to pilot test two ELM-based vaccine education interventions to improve maternal vaccine receipt in the perinatal period. Women were approached by trained study personnel in the waiting rooms of antenatal clinics in Atlanta, Georgia, US, if they appeared to be eligible for the study (based on pregnancy status, age, and race) and were asked if they would participate in an interview on women's health education. Participants (n = 106) were randomly assigned to the control group or to one of two vaccine education interventions based on the ELM central processing route: 1) an affective messaging video titled "Pregnant Pause", which showed physicians providing detailed information on Tdap and influenza vaccines, the severity of pertussis and influenza, how the vaccines protect pregnant women and newborns, safety information, and the current Advisory Committee on Immunization Practices (ACIP) recommendations, or 2) a cognitive messaging iBook titled "Vaccines for a Healthy Pregnancy" [PDF], which provided information through a question-and-answer (interactive) format. Both vaccine education interventions were completed on a handheld electronic tablet device and were designed to take no longer than 20 minutes, to enable patients to complete them while waiting for their prenatal appointments.

Ninety-five (90%) of the women completed follow-up after giving birth, of which 34 were in the control group, 31 were in the video group, and 30 were in the iBook group. Overall, 32% of respondents reported receiving Tdap vaccine during the perinatal period. In the control group, 18% of women were vaccinated with Tdap in the perinatal period; in the iBook group, 50% of women were vaccinated with Tdap in the perinatal period (risk ratio (RR) [for comparison with control group]: 2.83; 95% confidence interval (CI), 1.26-6.37); and in the video group, 29% were vaccinated with Tdap in the perinatal period (RR: 1.65; 95% CI, 0.66-4.09). Notably, most women who reported receiving Tdap in the perinatal period received it immediately postpartum; only a small number were vaccinated during pregnancy and in accordance with the current recommendations.

Participant engagement in the intervention, as measured by the observing interviewer, was higher in the video group (88% very engaged or engaged) than in the iBook group (56% very engaged or engaged). More women in the video group said they felt they could relate to the educational material compared with women in the iBook group (68% vs. 37%, p=0.02), and they were more likely to believe that there was evidence to support the vaccine information presented (77% vs. 50% said the producers of the video and iBook, respectively, could provide evidence to support vaccine claims, p=0.03). The video was also easier to understand, with 97% saying they clearly understood it, compared with 77% of iBook users (p=0.02).

Among women who reported they did not receive Tdap during pregnancy, the 2 most frequent reasons were not receiving a recommendation for Tdap from their doctor (48%) and not knowing about Tdap (44%). Other reasons given were unsure what Tdap was for (25%), did not think they were at risk for tetanus, diphtheria, or pertussis (19%), and do not generally take vaccines (14%). This signifies that, even when women were provided with tailored information on Tdap, some women did not process the information or remember the messages that were presented. A smaller percentage of women in the iBook group reported that they were unsure what Tdap was for (15%, compared with 28% in the control group and 31% in the video group), but differences were not statistically significant.

Of the 2 education interventions, the iBook was associated with higher Tdap uptake in the perinatal period. The video was designed to evoke an emotional response with its affective entertainment-education storyline, and this approach demonstrated a modest but non-significant improvement in Tdap vaccination during the perinatal period, despite women seeming to be more engaged with it.

Women's reported intention to receive Tdap in the next pregnancy improved in all 3 arms from baseline to follow-up, which may be because of involvement in the study itself resulting in greater awareness of Tdap. However, this study did not follow women to their next pregnancy to determine whether intent to be vaccinated in the future translated into actual vaccination.

In conclusion: "Provider recommendation for Tdap vaccination was associated with increased likelihood of vaccination in the perinatal period, but health care providers may not be providing adequate information to all women, resulting in overall sub-optimal Tdap vaccination of pregnant women. This study suggests that education interventions that provide targeted information for pregnant women in an interactive manner may be useful in improving Tdap vaccination in the perinatal period, but larger studies among more heterogeneous populations are needed."