- Safe Water System (SWS)
- Safety, Blood Supply — see Blood Safety
- Safety, Medication — see Medication Safety
- Saint Louis Encephalitis (SLEV) — see St. Louis Encephalitis (SLEV)
- Salmonella Infection
- Salmonella Paratyphi Infection — see Typhoid Fever and Paratyphoid Fever
- Salmonella Typhi infection — see Typhoid Fever and Paratyphoid Fever
- Salmonellosis — see Salmonella Infection
- Salt
- Heart Disease
- High Blood Pressure
- Sanitation & Hygiene, Global — see Global Water, Sanitation, & Hygiene (WASH)
- Sarcocystis Infection — see Sarcocystosis
- Sarcocystosis
- Sarcoptes scabiei var. hominis — see Scabies
- Sarin (GB)
- SAS Programs for Growth Charts
- Scabies
- Schistosoma Infection — see Schistosomiasis
- Schistosomiasis
- School Health
- Healthy Youth
- School Health Index (SHI)
- School Violence
- Science
- Science Ambassador Fellowship
- Science Clips
- Science, CDC Office of
- Screening for Critical Congenital Heart Defects
- Scrub Typhus — see Typhus Fevers
- Seasonal Flu
- Seat Belts
- Secondhand Smoke
- Seizure disorder
- Epilepsy
- Select Agent Program
- Sepsis
- Septic shock — see Sepsis
- Septicemia — see Sepsis
- Sex Trafficking
- Sexual Violence
- Sexually Transmitted Disease Surveillance Reports
- Sexually Transmitted Infections (STIs)
- Sharps Safety
- Shift Work — see Work Schedules
- Shiga toxin-producing E. coli — see E. coli Infection
- Shigella Infection
- Shigellosis — see Shigella Infection
- Shingles
- Shingles Vaccination
- Sick Building Syndrome — see Indoor Environmental Quality
- Sickle Cell Disease
- Silica
- Single Gene Disorders
- Sinus Infection
- Sinusitus — see Sinus Infection
- Skin Cancer
- Skin Conditions, Occupational
- Sleep and Sleep Disorders
- Sleeping Sickness
- Small Business
- Small Business Innovation Research (SBIR) Program
- Smallpox
- Smokeless (Oral) Tobacco
- Smoking and Tobacco Use
- Social Connectedness
- Social Determinants of Health
- Social Media Tools
- Social Vulnerability Index (SVI)
- Sodium Azide
- Sodium cyanide — see Cyanide
- Sodium — see Salt
- Soft Tick Relapsing Fever (STRF) — see Tick and Louse-borne Relapsing Fevers
- Soil-Transmitted Helminths
- Solid Waste Industry
- Soman (GD)
- Sore Mouth Disease — see Orf Virus Infection
- Sore Throat
- Southern Tick-Associated Rash Illness (STARI)
- Speakers Bureau, CDC — see CDC Speakers Bureau
- Specimen Submission
- Spina Bifida
- Spirillum minus Infection — see Rat-Bite Fever (RBF)
- Spirometry Training
- Sporothrix infection — see Sporotrichosis
- Sporotrichosis
- St. Louis Encephalitis (SLEV)
- Stalking
- Staph — see Staphylococcus aureus Infection
- Staphylococcal Food Poisoning
- Staphylococcus aureus Food Poisoning — see Staphylococcal Food Poisoning
- Staphylococcus aureus Infection
- State and Local Integrated Telephone Survey (SLAITS)
- State Preparedness
- State, Tribal, Local & Territorial Public Health Professionals Gateway — see Public Health Professionals Gateway
- STEADI – Older Adult Fall Prevention
- STEM at CDC
- Stephen B. Thacker CDC Library
- Library
- Steven M. Teutsch Prevention Effectiveness Fellowship
- STI Prevention
- Stibine — see Arsine
- Still Going Strong
- Stillbirth
- Stimulus — see Recovery Act
- Stop Overdose
- Storms and Floods
- Strategic Foresight at NIOSH
- Strep Infection, Group A — see Group A Strep Disease
- Strep Infection, Group B — see Group B Strep Disease
- Streptobacillus moniliformis Infection — see Rat-Bite Fever (RBF)
- Streptococcus Laboratory
- Streptococcus pneumoniae Infection
- Stress, Occupational
- Stroke
- Strongyloides Infection
- Strongyloidiasis — see Strongyloides Infection
- Strychnine
- Sudden Infant Death Syndrome (SIDS)
- Sudden Infant Death Syndrome (SIDS) and Vaccines
- Suicide Prevention
- Sulfur Mustard — see Mustard Gas (H, HD, and HT)
- Super Warfarin
- Surgeon General’s Reports on Tobacco
- Surgical Site Infection (SSI)
- Surveillance Case Definitions for Current and Historical Conditions
- Surveillance Reports, Sexually Transmitted Disease — see Sexually Transmitted Disease Surveillance Reports
- Surveillance Resource Center
- Surveillance Strategy
- Surveys & Data Collection Systems
- Survivorship, Cancer — see Cancer Survivors
- Swimmer’s Itch
- Swimming — see Water, Recreational
- Swimming-related Illness — see Recreational Water Illnesses (RWI)
- Swine Influenza
- Syndromic Surveillance — see National Syndromic Surveillance Program (NSSP)
- Syphilis
- Syringe Services Programs (SSPs)
- Systemic lupus erythematosus — see Lupus (SLE)
It's never too early or too late to work towards being the healthiest you.