Arms | Intervention description | Intervention delivery |
---|---|---|
Control arm | 1. Test prompts: information about risk of syphilis infection and local free syphilis test services. | • Text messages will be sent at enrollment, three-month visit, and six-month visit via WeChat. • Voluntary report testing result to the platform. |
Standard self-testing arm | 1. Test prompts: information about risk of syphilis infection and local free syphilis test services. 2. Self-testing: free home delivery of self-testing package. | • Text messages will be sent at enrollment, three-month visit, and six-month visit via WeChat. • Provision of syphilis self-testing service: self-testing package can be ordered online and sent to participant through postal mail. Maximum one self-testing package per month. • Voluntary report self-test result to the platform. |
Lottery incentivized self-testing arm | 1. Test prompts: information about risk of syphilis infection and local free syphilis test services. 2. Self-testing: free home delivery of self-testing package. 3. Lottery incentive: lottery draw with 10% chance to win 100 RMB for participants have confirmed uptake of syphilis testing. | • Text messages will be sent at enrollment, three-month visit, and six-month visit via WeChat. • Provision of syphilis self-testing service: self-testing package can be ordered online and sent to participant through postal mail. Maximum one self-testing package per month. • Voluntary report self-test result to the platform. • Lottery draw will be given to participants who get syphilis tested and upload photo verification to the platform. |