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Learning Center
Stomach flu: How long am I contagious?
Depending on which virus causes your stomach illness, you can be contagious from a few days to two weeks or more.
Cold and flu viruses: How long can they live outside the body?
Some viruses are more resilient than you may think. Learn more about how they spread and how to protect yourself.
Does sunscreen expire?
Wondering whether sunscreen expires? Get the facts about how long sunscreen lasts.
Sitting risks: How harmful is too much sitting?
Sitting for long periods — such as in front of the TV or at a desk — appears to increase risk of death from cardiovascular disease and cancer.
High-dose flu vaccines: How are they different from other flu vaccines?
High-dose flu vaccines are flu vaccines for older people.
Heart attack prevention: Should I avoid secondhand smoke?
It's possible that secondhand smoke can irritate the arteries and increase the risk of a heart attack.
Dental floss vs. water flosser: Which is better?
Cleaning between your teeth every day is an important part of good oral health.
When to brush your teeth
When should you brush your teeth? Learn how to protect your oral health.
Tetanus shots: Is it risky to receive 'extra' boosters?
For adults, tetanus shots are recommended every 10 years.
Calcium supplements: When should they be taken?
Timing matters when taking these supplements. Learn how to take them.