- Safety of blood supply
- see Blood safety - Sale of sexual services
- see Sex workers and clients - Schools
- Seafarers
- see Mobile populations - Security and HIV/AIDS
- Sentinel surveillance
- see Surveillance - Sex education
- see Health education - Sex workers and clients
- Sexual and reproductive health
- Sexual minorities
- see Transgender - Sexuality
- Sexuality
- see Transgender - Sexually transmitted infection
- Social Determinants
- see Determinants of the epidemic - Standard precautions
- see Blood safety - STI
- see Sexually transmitted infection - Stigma and discrimination
- Strategic planning and management
- Strategic plans
- see National plans - Support
- see Care and support - Surveillance