JMIR Publications

ABSTRACT

Background:

Men who have sex with men (MSM) are at high risk of contracting Human papillomavirus (HPV) and its related diseases. HPV vaccination is highly effective in preventing vaccine-type genital warts and cancers among MSM.

Objective:

The primary objective of this randomized controlled trial (RCT) was to evaluate the relative efficacies of two online, theory-based interventions with and without brief motivational interviewing (MI) over the phone in increasing HPV vaccination completion (receipt of three required doses) within a 24-month follow-up period, as compared to the control group.

Methods:

A three-arm parallel-group RCT was conducted between July 2017 and December 2019. Five telephone surveys were conducted at Baseline, Month 3, 6, 9 & 24 by blinded interviewers. Participants were Hong Kong Chinese speaking MSM aged 18 to 45 years having regular Internet access. Those who had ever received HPV vaccination were excluded. A total of 624 participants were randomized into either the Group HC (n=208), the Group HC-MI (n=208), and the control group (n=208); 459 (73.6%) completed follow-up evaluation at Month 24. Participants in the Group HC received an online tutorial developed based on the Health Belief Model. On top of the same online tutorial, the Group HC-MI received brief MI over the phone. Reminders were sent to participants of the Group HC and Group HC-MI 1, 2, 4, 6 and 8 months afterwards. Participants in the control group received online health communication messages irrelevant to HPV or HPV vaccination. The research team validated self-reported HPV vaccination uptake. Intention-to-treat analysis was used for outcome analyses. Logistic regression models and linear regression models were used to test the between-group differences in primary and secondary outcomes. Baron and Kenny’s methods were used to test the mediation hypothesis.

Results:

Participants in the Group HC-MI reported significantly higher validated completion of HPV vaccination at Month 24 than the control group [17.3% (36/208) versus 7.2% (15/208), adjusted odds ratios (AOR): 1.57, 95%CI: 1.14, 2.17, p=.006]. However, the difference in HPV vaccination completion between the Group HC and the control group (p=.17), or between the Group HC-MI and the Group HC (p=.13) was not statistically significant. The association between randomization status (Group HC-MI versus control) and HPV vaccination completion became statistically non-significant (from p=.006 to p=.06) after controlled for changes in perceived susceptibility to HPV/HPV-related diseases (Month 24 versus baseline), whereas perceived susceptibility remained strongly associated with HPV vaccination uptake in the model (p<.001). The results suggested that change in perceived susceptibility fully mediated the intervention effect.

Conclusions:

The theory-based online tutorial with brief MI over the phone was effective in increasing HPV vaccination completion among MSM in Hong Kong, China. Perceived susceptibility was an active theoretical component leading to behavioral changes. Local and international dissemination and implementation research are greatly warranted. Clinical Trial: ClinicalTrial.gov, number NCT03286907