- Aortic Aneurysm
- Abortion Surveillance
- Abuse, Child
- Abuse, Elder
- Abusive Head Trauma
- Acanthamoeba Infection
- Adverse Childhood Experiences (ACE)
- Acinetobacter Infection
- ACIP Vaccine Recommendations and Guidelines
- Acquired Immune Deficiency Syndrome (AIDS)— HIV
- Active Bacterial Core surveillance (ABCs)
- Acute Bronchitis
- Acute Flaccid Myelitis (AFM)
- Adenovirus Infection
- Adenovirus Vaccination
- Attention-Deficit/Hyperactivity Disorder (ADHD)
- Adolescent Health
- Adolescent Pregnancy — Teen Pregnancy
- Adult Vaccinations
- Advanced Molecular Detection (AMD)
- Adverse Drug Events — Medication Safety
- Adverse Events Following Immunization — Vaccine Adverse Event Reporting System (VAERS)
- Aerosols
- AFIX Immunization Strategy
- Agents, Chemical — see Chemical Agents
- Aging
- Aging in the Workplace
- Agricultural Safety — see Farm Worker Injuries
- Agricultural Water
- Air Pollutants
- Air Quality
- Alcohol
- Alcohol & Pregnancy
- Alcohol Use
- Underage Drinking
- Alcohol & Pregnancy
- Algal Blooms, Harmful (HABs)
- Alkhurma hemorrhagic fever (AHF)
- Alpha-gal Syndrome
- Alveolar echinococcosis — see Echinococcosis
- Alzheimer’s Disease
- Amebiasis
- Amebic Meningitis
- American Indian and Alaska Native Worker Initiative
- American Trypanosomiasis — see Chagas Disease
- Ammonia
- Amphibians, Infections from — see Reptiles and Amphibians
- Amyotrophic Lateral Sclerosis (ALS)
- Anaplasma phagocytophilum Infection — see Anaplasmosis
- Anaplasmosis
- Ancylostoma duodenale Infection — see Soil-Transmitted Helminths
- Angiostrongylus Infection — see Rat Lungworm Disease
- Animal and Animal Product Importation — see Importation of Animals, Animal Products
- Animal Product Importation — see Importation of Animals, Animal Products
- Animal-Related Diseases
- Anisakiasis — see Anisakis Infection
- Anisakis Infection
- Anthrax
- Anthrax in the Workplace
- Anthrax Vaccination
- Anthropometry
- Antibiotic Prescribing and Use
- U.S. Antibiotic Awareness Week (USAAW)
- Antibiotic Resistance — see Antimicrobial Resistance
- Antibiotic Stewardship
- Antimicrobial Resistance
- Antimicrobial Resistance Laboratory Networks
- Antimicrobial Stewardship — see Antibiotic Stewardship
- Antineoplastic Agents
- Aortic Aneurysm
- Aortic Dissection — see Aortic Aneurysm
- Arctic Investigations
- Arenavirus Infections
- ARRA — see Recovery Act
- Arsenic
- Arsine
- Arthritis
- Ascariasis — see Soil-Transmitted Helminths
- Ascaris Infection — see Soil-Transmitted Helminths
- Aseptic Meningitis — see Viral Meningitis
- Aspergillosis
- Aspergillus Infection — see Aspergillosis
- Assisted Living Facilities, Infection Prevention in — see Long-Term Care Facilities, Infection Prevention in (LTCFs)
- Assisted Reproductive Technology (ART)
- Assurance of Confidentiality — see Certificate of Confidentiality
- Asthma
- Asthma and Influenza
- Influenza
- Asthma in the Workplace
- At-Risk — see Social Vulnerability Index (SVI)
- Atrial fibrillation (AFib, AF)
- Attention Deficit/Hyperactivity Disorder — see ADHD
- Autism
- Genetics and Genomics
- Autism and Thimerosal — see Thimerosal (Mercury) and Vaccines
- Avian Flu in the Workplace
- Avian Influenza
It's never too early or too late to work towards being the healthiest you.