Trial Outcomes & Findings for txt2protect: Using Text Messaging to Increase HPV Vaccination Among Young Sexual Minority Men (NCT NCT02994108)

Study recruitment took place from January through early September 2018 in the Chicago area.

Although 155 participants completed the baseline survey, only 150 of them were randomized. A double screening protocol was used to ensure participants who had already been vaccinated were not accidentally enrolled. Five participants reported receiving a dose of HPV vaccine on baseline so they were no longer eligible for the RCT.

txt2protect: Using Text Messaging to Increase HPV Vaccination Among Young Sexual Minority Men

Intervention feasibility will be evaluated by retention in the RCT. The retention rate will be computed at the end of the 9-month trial by dividing the total number of participants who completed the trial (i.e., completed the 9-month assessment) by the total number of participants who were randomized to the treatment or control condition at the beginning of the trial. An 80% 9-month retention rate will be used to indicate a feasible intervention.

Intervention acceptability for the first 3 weeks of the intervention (Phase 1) will be assessed at the 3-week assessment. The scale includes both open-ended ("What did you like about the program? What could be improved?") and 12 closed-ended questions (e.g., "I would recommend a program like this to my friends" 1=strongly disagree to 5=strongly agree). Closed-ended items were combined to compute an average score (minimum value = 1; maximum value = 5). Higher scores indicate greater satisfaction with the program. An average score ≥4 will be used to indicate an acceptable intervention.

Intervention acceptability for the full intervention will be assessed at the end the 9-month trial. The scale includes both open-ended ("What did you like about the program? What could be improved?") and 11 closed-ended questions (e.g., "I would recommend a program like this to my friends" 1=strongly disagree to 5=strongly agree). Closed-ended items will be combined to compute an average score (minimum value = 1; maximum value = 5). Higher scores indicate greater satisfaction with the program. An average score ≥4 will be used to indicate an acceptable intervention.

A final confirmatory assessment of HPV vaccination status will be conducted at the 9-month follow-up. Participants will be asked whether they received any doses of HPV vaccine (yes/no) since baseline and if yes, the number of doses and received. Vaccination status will be confirmed by consulting the Illinois Comprehensive Automated Immunization Registry (I-CARE). HPV vaccine initiation was defined as receipt of one or more doses of HPV vaccine by the end of the 9-month trial.

A final confirmatory assessment of HPV vaccination status will be conducted at the 9-month follow-up. Participants will be asked whether they received any doses of HPV vaccine (yes/no) since baseline and if yes, the number of doses received. Vaccination status will be confirmed by consulting the Illinois Comprehensive Automated Immunization Registry (I-CARE). HPV vaccine completion was defined as receipt of three doses of HPV vaccine by the end of the 9-month trial.

Assessed with two questions (e.g., "HPV can cause anal cancer.") interspersed among other true/false questions assessing HIV/STI knowledge. Participants received one point for each correct response and zero points for incorrect and "don't know" responses. Points were summed to create a composite score that ranged from 0 to 2.

Assessed with one item: "My attitude toward getting vaccinated for HPV in the next 9 months is..." 1 = very negative to 5 = very positive.

Assessed with one item: "People who are important to me would want me to get vaccinated for HPV in the next 9 months." 1 = strongly disagree to 5 = strongly agree.

Assessed with four items (e.g., "If you don't get the HPV vaccine, what do you think are the chances that you will get HPV?" 1 = very unlikely to 5 = very likely).

Assessed with four items (e.g., "How serious would each of the following be for you: If you developed warts on your penis or scrotum?" 1 = not at all serious to 5 = very serious).

Assessed with two items (e.g., "How much regret would you feel if you decided not to get the HPV vaccine and later developed genital or anal warts?" 1 = none to 5 = quite a lot).

Assessed with one item: "To what extent is whether or not you get vaccinated for HPV in the next 9 months under your control?" 1 = not at all to 5 = completely.

Assessed with one item: "Assuming you wanted to, how hard or easy would it be for you to get vaccinated for HPV in the next 9 months?" 1 = very hard to 5 = very easy.

Assessed with one item: "I intend to get vaccinated for HPV in the next 9 months." 1 = strongly disagree to 5 = strongly agree.