Background Expedited partner therapy (EPT) is commonly provided by prescription; however, the efficacy of this modality is unknown. We examined whether EPT prescriptions are filled when the cost barrier is removed. Methods To track EPT prescription fill rates, we used single-use pharmacy vouchers that covered the cost of azithromycin, 1 g (chlamydia treatment). We recruited clinical sites to distribute vouchers to patients with chlamydia who would receive an EPT prescription under clinic policies. When distributing vouchers, sites recorded and retained: voucher unique identifier, sex and age of index patient, distribution date, and whether partner name was written on the EPT prescription. Pharmacists receiving vouchers entered the identifier, sex and age of presenting person, and redemption date into a standard pharmacy claim transmission system. Data for redeemed vouchers were retrieved from an industry portal and linked with data retained at clinical sites. Results Thirty-two clinical sites distributed 931 vouchers during September 2017 to January 2019; 382 (41%) were redeemed. Vouchers distributed to patients 18 years or younger (49 [30%] of 163) were less likely to be redeemed compared with those distributed to patients older than 18 years (322 [44%] of 736; P = 0.001). Just over half of vouchers were redeemed the same day (196 [56%] of 352) and 1 mile or less from the clinical site (188 [54%] of 349). After excluding an outlier site, vouchers accompanied by EPT prescriptions including a partner name (15 [56%] of 27) were more likely to be redeemed than those lacking a name (83 [34%] of 244; P = 0.03). Conclusions Less than half of EPT prescriptions were filled, even when medication was free. Whenever possible, EPT should be provided as drug-in-hand.

transmitted infections (STI). Providers struggled to differentiate event-specific anxieties from more chronic, underlying anxietyrelated conditions. Three barriers constrained the providers' abilities to effectively address MHSU service needs: 1) clinic mandates or funding models (specific to STI/HIV or reproductive health); 2) 'silo-ing' (i.e., physical and administrative separation) of services; and, 3) limited familiarity with MSHU service referral pathways. In response to these barriers and acknowledging the prevalence and prominence of MHSU concerns among clients, participants described actionable solutions. 1) Reduce silos, by clarifying referral pathways from sexual health clinics to MHSU providers. 2) Co-locate sexual health and MHSU services. 3) Assess the broader health needs of high-anxiety and low-STI risk clients who frequently access sexual health services. Conclusion Sexual health clinicians in British Columbia generally affirm the results of previous, quantitative and clientfocused research showing high rates of MHSU-related needs among sexual health clinic clients. Providers prioritized specific short-term (referral-focused) and long-term (healthcare reorganization) solutions for improving access to MHSU for those using sexual health services. Disclosure No significant relationships.