biostudies-literatureSpence TNational Institute for Health and Care Research2339https://www.ebi.ac.uk/biostudies/studies/S-EPMC11360737biostudies-literatureUnknown24(1)<h4>Background</h4>Sexually transmitted infections (STIs) are a serious public health issue in many countries. Online postal self-sampling (OPSS) is increasingly used to test for STIs, a trend accelerated by the COVID-19 pandemic. There remains limited understanding of how service users experience OPSS and what leads them to access it over clinic-based services, or vice versa. This research seeks to address these gaps, by undertaking a large qualitative study which sits within the ASSIST study, a mixed-methods, realist evaluation of OPSS.<h4>Methods</h4>Participants were recruited via clinic-based and online sexual health services in three case study areas in England. Purposive sampling was used to over-represent populations disproportionately affected by poor sexual health: young people; BMC public healthHow does online postal self-sampling (OPSS) shape access to testing for sexually transmitted infections (STIs)? A qualitative study of service users.PMC11360737NIHR129157Dewsnap CGibbs JDay SApea VMercer CHMohammed HWilliams ASpence TSullivan ARoss JDCCrundwell DBurns FSheringham JHowarth AJackson LWinter AWong GReid DfalseHow does online postal self-sampling (OPSS) shape access to testing for sexually transmitted infections (STIs)? A qualitative study of service users.<h4>Background</h4>Sexually transmitted infections (STIs) are a serious public health issue in many countries. Online postal self-sampling (OPSS) is increasingly used to test for STIs, a trend accelerated by the COVID-19 pandemic. There remains limited understanding of how service users experience OPSS and what leads them to access it over clinic-based services, or vice versa. This research seeks to address these gaps, by undertaking a large qualitative study which sits within the ASSIST study, a mixed-methods, realist evaluation of OPSS.<h4>Methods</h4>Participants were recruited via clinic-based and online sexual health services in three case study areas in England. Purposive sampling was used to over-represent populations disproportionately affected by poor sexual health: young people; 2024-01-01T00:00:00Z2024 Aug2025-04-05T12:29:42.97Z2025-04-05T12:29:42.97ZS-EPMC113607373919875110.1186/s12889-024-19741-x