To Örebro University

Background: Despite greater sensitivity of vaginal swabs compared to urine for detection of STIs and high acceptability in clinical settings, acceptability and feasibility of home-based self-collected vaginal swabs for research are less certain. We undertook development work to test these attributes for self-collected vaginal swabs for Natsal-4, a probability sample, interviewer-administered, survey of the ritish population aged 16-59 years.

Methods: We conducted two pilot studies in 2021-22. After completing an interview, all participants identifying as cisgender women were invited to provide three self-collected vaginal swabs, with procedures for providing samples during or afte rface-to-face interviews or after remote interviews. Samples were posted to the laboratory. Consent was provided with the understanding of non-return of results. Participants declining vaginal swabs were invited to provide urine. Interviewers were not clinically trained. Qualitative follow-up interviews were conducted with participants and interviewers provided feedback.

Results: Of the 153 cisgender women interviewed, 77 (50%) agreed to provide a vaginal swab, and 22 preferred to provide urine, resulting in an overall biosample consent rate of 65%. Of these, 60 swabs and 18 urine samples were received (Figure), resulting in an overall response of 51% (39% for vaginal swabs). Of the 77 who consented to provide swabs, 43 (56%) were during face-to-face interviews, of which 95% were received, compared to 13 (17%) agreeing to collection after face-to-face with 54% received, and 21 (27%) choosing remote interviews with 57% received. Fourteen participants (10 provided swabs) gave follow-up interviews and seven interviewers provided feedback. Participants conveyed their motivation to support research by giving samples. Interviewers were surprised at participants’ willingness to provide swabs. Reasons for not providing a swab included the belief that it was uncomfortable, too intimate or not relevant for their circumstances, or that urine was easier to collect.

Conclusion: Our findings show that self-collection of vaginal swabs at home facilitated by non-clinically trained interviewers for a population-based probability survey is feasible and acceptable. Mode of interview and timing of sample collection are important as they affect response rate. Vaginal swab collection was incorporated into the main Natsal-4study with similar response to date.