Health Topics A-Z

Vaccine Hesitancy

Delay or refusal of vaccination despite availability.

Vaccine Side Effects

The expected reactions after vaccination, and the rare ones that need attention.

Vaccines During Pregnancy

Vaccines given in pregnancy to protect the pregnant person and to pass antibodies to the baby before birth.

Vaccines for Travel

Immunizations recommended or required for particular destinations.

Vaping and E-Cigarettes

Battery-powered devices that heat a liquid, usually containing nicotine, into an aerosol that is inhaled.

Vaping and Teens

Using e-cigarettes and other vaping devices, which heat a liquid, usually containing nicotine, into an aerosol that is inhaled.

Vegetarian and Vegan Diets

Eating patterns that exclude meat, or all animal products.

Vitamin B12 Deficiency

Too little vitamin B12 for red blood cell production and nerve health.

Vitamin C

A water-soluble vitamin needed for collagen production and immune cell function.

Vitamin D

A fat-soluble vitamin that helps the body absorb calcium and phosphorus and keep bones strong.

Vitamin D and Bone

The role of vitamin D in calcium absorption and bone mineralization.

Vitamin D and Hormones

Vitamin D's role as a hormone regulating calcium, and its interaction with the parathyroid glands.

Walking

The most accessible form of moderate activity, requiring no equipment, venue or skill.

Warming Up and Cooling Down

Raising tissue temperature and rehearsing the movement before training, and slowing down gradually afterward.

Warning Signs

The symptoms that warrant a checkup because they can indicate cancer.

Weekly Activity Targets

The amount and type of physical activity the Physical Activity Guidelines for Americans ask of adults each week.

Weight and Mental Health

The two-way relationship between weight, mood, self-image and eating behavior.

Weight Fluctuation

The day-to-day movement on the scale that has nothing to do with body fat.

Weight Maintenance

Keeping weight off after losing it, which has its own evidence base and its own skills.

West Nile Virus and Mosquitoes

A virus spread by the bite of infected mosquitoes and the leading cause of mosquito-borne disease in the continental US.

When Caring Ends

The period after caregiving stops, through bereavement or a move into a care facility.

When to Go to the ER

The hospital emergency room (emergency department), open around the clock for serious injury and illness.

Whole Grains

Grains that keep the bran, germ and endosperm, such as whole-wheat flour, oats, brown rice and barley.

Wildfire Smoke

Smoke from wildfires, which contains fine particles (PM2.5) that can travel hundreds of miles and harm the lungs and heart.

Work-Related Stress

Harmful physical and emotional reactions that occur when the demands of a job do not match a worker's resources or needs.

Workplace First Aid

The first aid provision employers must make, and what to do in the first minutes.

Workstation Setup

Arranging a desk, chair and screen to reduce discomfort during sustained work.

Wound Care

Cleaning and dressing minor cuts and scrapes so they heal without infection.

Young Caregivers

Children and teenagers providing care for a family member.

Zinc

A trace mineral needed for immune function, wound healing and taste.