The Effect of a Web-Based Cervical Cancer Survivor's Story on Parents' Behavior and Willingness to Consider Human Papillomavirus Vaccination for Daughters: Randomized Controlled Trial

"...this trial could provide a novel insight into digital educational methods for promoting disease prevention through vaccination to the general public."

Providing adequate information to parents who have children eligible for human papillomavirus (HPV) vaccination is considered to be essential to overcoming vaccine hesitancy in Japan, where proactive government recommendations have been suspended since 2013 (leading to a vaccination rate estimated to be below 1%). The aim of this trial is to assess the effect of viewing a short online film sharing a cervical cancer survivor's story on the willingness of parents to have their daughters vaccinated against HPV.

In this study, a 4-minute-long film was used as the intervention. In the film, a singer, songwriter, and actress in Japan talked about her experience with cervical cancer - from the diagnosis to the sequelae of first-line therapy. Seven messages were inserted as subtitles throughout her talk:

• "She was diagnosed with cervical cancer at 31 years old."
• "In Japan, approximately 10,000 people a year are diagnosed with cervical cancer and about 3,000 people die annually."
• "Undergoing surgery wasn't the end of suffering."
• "The burden of cervical cancer was greater than expected and is relatively seen in younger ages."
• "Cervical cancer can be prevented by HPV vaccination and Pap smears."
• "A lot of children have lost their chance to prevent cervical cancer in Japan."
• "Why don't we take action for our children's future?"

In this double-blinded, randomised controlled trial (RCT) implemented online, the researchers enrolled 2,175 participants aged 30-59 years in March 2020 via a webpage and provided them with basic information about the benefits and adverse effects of HPV vaccination, with the aim of sharing scientific nonnarrative information. Participants were randomly assigned (1:1) to see the short film or nothing, stratified by sex (male vs. female) and willingness for HPV vaccination prior to randomisation (yes vs. no). The primary endpoint was the rate of parents who agreed to HPV vaccination for their daughters. The secondary endpoint was the rate of parents who agreed to HPV vaccination for their daughters and the HPV vaccination rate at 3 months. Risk ratio (RR) was used to assess the interventional effect.

Of 2,175 participants, 1,266 (58.2%) were men and 909 (41.8%) were women. A total of 191 (8.8%) participants were willing to consider HPV vaccination prior to randomisation. Only 339 (15.6%) participants were aware of the benefits of HPV vaccination; in contrast, 562 (25.8%) participants were aware of the adverse events of HPV vaccination. Although only 476 (21.9%) of the respondents displayed a willingness to vaccinate their daughters for HPV, there were 7.5% more respondents in the intervention group with this willingness immediately after watching the short film (RR 1.41, 95% confidence interval (CI) 1.20-1.66). Also, intent to disseminate HPV vaccination information to family members, friends, or others on social media was higher in the intervention group (RR 1.41, 95% CI 1.20-1.66).

In a subanalysis, the willingness in males to vaccinate their daughters was significantly higher in the intervention group (RR 1.50, 95% CI 1.25-1.81); however, such a difference was not observed among females (RR 1.21, 95% CI 0.88-1.66). In fact, differences between sexes were identified in all questions. Fathers were more likely to have an affirmative attitude toward HPV vaccination for their daughters in the intervention group (fathers: RR 1.50, 95% CI 1.25-1.81; mothers: RR 1.21, 95% CI 0.88-1.66). In addition, fathers in the intervention group were more likely to disseminate HPV vaccination information to someone on social media.

In the follow-up survey at 3 months, 1,807 (83.1%) participants responded. Of these, 149 (8.2%) responded that they had had their daughters vaccinated during the 3 months, even though the effect of the intervention was not evident: 77 (7.9%) in the intervention group and 72 (8.7%) in the control group.

In sum: "This study demonstrated a positive immediate effect on the willingness for HPV vaccination in parents who have daughters, following intervention using a short film on cervical cancer, especially among fathers. Such an approach is promising for overcoming the hesitancy toward HPV vaccination. Additionally, this RCT showed the importance of the father's role in improving the HPV vaccination rate and overcoming vaccine hesitancy." While they propose a few explanations for these gender-specific findings, they note that "little is known about parents' sex differences affecting the likelihood of HPV vaccination for their children....We need to...examine possible factors affecting the gender difference toward HPV vaccination".

Reflecting on the findings (e.g., the role of people's discussions with others about HPV vaccination on social media), the researchers note that, although face-to-face educational approaches with parents might be an effective way to improve awareness and understanding of the vaccination, online approaches are increasingly being explored in light of the rapid growth in the share of social media users worldwide. In some countries, including Japan, nationwide vaccine hesitancy in regard to HPV vaccination has been seen to be caused by online and offline dissemination of misleading beliefs. Thus, they propose that any strategy to encourage HPV vaccine uptake needs to consider the pros and cons of incorporating - and/or should account for the unforeseen impacts of - social media. Furthermore, because of the study's differential findings about the effectiveness of educational interventions between sexes, the identified strategy should be carefully tailored according to specific populations.

In conclusion: "An anecdotal cervical cancer survivor's story increases the willingness of Japanese parents to consider HPV vaccination for their daughters. However, this type of intervention might not sustain their motivation months afterward."