Usability of a Web-Based App for Increasing Adolescent Vaccination in Primary Care Settings: Think-Aloud and Survey Assessment
Authors: Staras Stephanie A S , Tauscher Justin , Vinson Michelle , Thompson Lindsay A , Gerend Mary A , Shenkman Elizabeth A 
Published: September 2024

Background
In the United States, only 58% of teens receive the recommended 2 doses of the human papillomavirus vaccine by 15 years of age. Overcoming vaccine hesitancy often requires effective communication between clinicians and parents to address specific concerns. To support this, we developed ProtectMe4, a multilevel, theory-informed web-based intervention designed to address parents’ vaccine-related questions and assist clinicians in discussing vaccine concerns for 4 adolescent vaccines.

Objective
This study aims to evaluate the usability of ProtectMe4 in routine care settings across 3 pediatric primary care clinics. Specifically, the study aims to (1) observe the proposed workflow in practice, (2) identify usability issues experienced by parents and clinicians, and (3) assess the perceptions of both parents and clinicians regarding the app’s usability.

Methods
On designated days in 2020 and 2021, the study team recruited parents of 11- to 12-year-old patients attending appointments with participating clinicians. We conducted think-aloud assessments during routine care visits and administered a usability survey after participants used the app. For parents, we simultaneously video-recorded the app screens and audio-recorded their commentary. For clinicians, observational notes were taken regarding their actions and comments. Timings recorded within the app provided data on the length of use. We reviewed the recordings and notes to compile a list of identified issues and calculated the frequencies of survey responses.

Results
Out of 12 parents invited to use the app, 9 (75%) participated. Two parents who were invited outside of the planned workflow, after seeing the clinician, refused to participate. For the parents whose child’s vaccination record was identified by the app, the median time spent using the app was 9 (range 6-28) minutes. Think-aloud assessment results for parents were categorized into 2 themes: (1) troubleshooting vaccine record identification and (2) clarifying the app content and purpose. Among the 8 parents who completed the survey, at least 75% (6/8) agreed with each acceptability measure related to user satisfaction, perceived usefulness, and acceptance. These parents’ children were patients of 4 of the 7 participating clinicians. Consistent with the planned workflow, clinicians viewed the app before seeing the patient in 4 of 9 (44%) instances. The median time spent on the app per patient was 95 (range 5-240) seconds. Think-aloud assessment results for clinicians were grouped into 2 themes: (1) trust of app vaccine results and (2) clarifying the app content. On the survey, clinicians were unanimously positive about the app, with an average System Usability Scale score of 87.5 (SE 2.5).

Conclusions
This mixed methods evaluation demonstrated that ProtectMe4 was usable and acceptable to both parents and clinicians in real-world pediatric primary care. Improved coordination among clinic staff is needed to ensure the app is consistently offered to patients and reviewed by clinicians before seeing the patient.