Evaluation of Two Health Education Interventions to Improve the Varicella Vaccination: A Randomized Controlled Trial from a Province in the East China

Varicella was a universal childhood disease before the era of varicella vaccine (VarV), coverage of which remains suboptimal in Zhejiang province, China. This study aimed to: (i) evaluate the effects of two different education interventions - one involving a messaging video and one a messaging booklet - based on the elaborating likelihood model (ELM), with respect to the improvement in the coverage of VarV; (ii) assess the timeliness of VarV vaccination by calculating the interval from the date of birth to the actual date of vaccination; and (iii) evaluate the difference in the effects on the knowledge and attitude of VarV vaccination between two interventions. The hope is that study might help to close the substantial evidence gap for rigorously evaluated health education interventions for increasing the acceptance and the coverage of VarV.

As explained here, ELM describes two types of information processing: (i) the central route, which is evoked when an individual has the motivation and ability to analyse a message, which tends to result in stronger behavioural changes; and (ii) the peripheral route, which is evoked when simplistic messages or peripheral cues are used; this tends to result in less enduring behavioural changes. In the context of a more enduring behavioural change required for vaccination, health education interventions that utilise the central route may be more appropriate. However, it is unclear how the message of vaccination can be effectively delivered, and very limited data exist on rigorously assessing its effects on the coverage of VarV.

In this prospective, randomised controlled trial (RCT), the study population consisted of 200 pregnant women who were ≥12 gestational weeks in Changxing County, Zhejiang Province, East China. Enrolled women were assigned into the control group, which did not receive any educational instructions or materials, or to one of two intervention groups, which were based on the ELM central processing route:

1. An affective messaging video, which was viewed on a handheld electronic tablet device; it was tailored specifically to the pregnant women and showed a doctor providing the detailed information on VarV vaccination, the severity of varicella, the safety profile of VarV, and the current recommendation on VarV vaccination. Of the two independent education interventions, the video was designed to evoke an emotional interaction with participants through its affective entertainment-education storyline.
2. A cognitive messaging booklet, which provided information through a question-and-answer format on the topic of the VarV vaccination, the disease burden of childhood varicella, the vaccine safety, and the current recommendation (which, per the ZJCDC, is one dose of VarV to children at 12 months of age - despite the vaccine not being included in the routine immunisation schedule).

Both the two interventions were designed to take no more than 15 minutes, to enable participants to complete them while waiting for their appointments. Study personnel recorded the time that participants spent on the interventions, and observed the women's attitudes toward the intervention activities. Furthermore, the VarV coverage at 12 and 24 months old was compared among the children of the three groups, and relative risks (RRs) were calculated by using the coverage of the control group as reference. The timeliness of VarV was also assessed. Furthermore, differences in the effects on the knowledge and attitude of VarV vaccination between the two interventions was evaluated.

Engagement in the intervention activities, as assessed by the proportion of participants scored as "engaged" or "very engaged", was significantly higher in the video group than in the booklet group (81.8% vs. 55.2%, p<0.05). The proportions of women who felt they learned some knowledge on the VarV, who believed in the information provided, and who clearly understood the education material did not significantly vary between the two intervention groups. The proportion of women who intended to vaccinate their children with VarV was significantly higher in the video group than the booklet group (93.9% vs 82.1%, p<0.05).

The VarV coverage of their children by 24 months of age was 86.4%, 76.1%, and 56.7% for the video group, the booklet group, and the control group, respectively. The RRs for the coverage of VarV at 24 months of age were 4.8 (95% confidence interval (CI): 2.06-11.3) for the video group and 2.4 (95% CI: 1.2-5.1) for the booklet group. The length of delays were 57.3 days in the video group, 76.9 days in the booklet group, and 100.6 days in the control group.

In short, the researchers found the VarV coverage among the two intervention groups was higher than that in the control group. Furthermore, the coverage in the video group was higher than that in the booklet group. They propose that the use of video as an educational media offers several advantages: (i) Video can remove the potential inconsistencies across the educators and balance the presentation of information to provide more standardised education. (ii) Individuals with lower literacy especially prefer the video-based education, as it can be easily understood. (iii) The video intervention can be a less resource-intensive way of delivering the educational information and can be administered in many forms, like the videotape, the digital video, the downloadable media files, and streaming videos from internet websites. These additional advantages would help the health education information spread quickly and reach broad audiences via social media.