Is Strep Throat Contagious?

Medically Reviewed by Kumar Shital, DO on September 22, 2020

When someone around you has a sore, scratchy throat, try to keep your distance. It might be strep throat. The bacteria that cause strep pass easily from person to person through close contact.

Learn how to spot someone who may have strep so you can stay away. And practice good hygiene so you -- and children in your care -- can stay well.

What Causes Strep Throat?

It’s caused by group A Streptococcus bacteria. They also can create infections of the:

Strep A bacteria normally live in your nose and mouth, and on your skin. Many people carry these microbes but don't get sick.

Strep throat usually isn’t serious. But when it is left untreated, it can cause complications such as:

How It Spreads

Strep throat makes the rounds when someone who has the infection coughs or sneezes. Droplets filled with bacteria spray into the air.

You can also catch strep when:

  • You touch something these droplets land on -- such as a doorknob or table -- and then rub your eyes, nose, or mouth.
  • You share personal items such as a fork or spoon, glass, or toothbrush with someone who is sick.
  • You kiss a person who has it.

When you get infected, you typically start to show symptoms about 2 to 5 days after you were exposed to the bacteria.

You can stay contagious for up to a month if you don't get treated. Antibiotics can prevent the infection from spreading. People who take antibiotics stop being contagious after about 24 hours.

Who’s Most Likely to Get It?

Strep throat often spreads in late fall and early spring, when children are in school. People 5 to 15 years old are most likely to get strep. But adults can get it, too.

People who have a weakened immune system have a higher chance of coming down with strep. This includes anyone who:

How to Prevent It

The best way to avoid strep is to stay away from anyone who looks or sounds sick. Signs can include:

Try not to share any personal items with someone who is sick. This includes:

  • Cups and plates
  • Knives, forks, spoons
  • Toothbrushes
  • Food and drinks

Wash your hands and your children's hands often. Or use an alcohol-based hand sanitizer. Always clean your hands before you eat and after you use the bathroom.

If you have strep, here are some things you or your child can do to avoid getting sick again:

  • Take all the medicine your doctor prescribed, even if you start to feel better. Some bacteria may live and rebound if you stop the medication too soon.
  • Once you've been on antibiotics for 2 to 3 days, throw out your old toothbrush and get a new one.
  • Stay out of work or school for at least 24 hours after you start taking an antibiotic.

Show Sources


American Academy of Family Physicians: "Sore Throat Causes & Risk Factors."

American Academy of Pediatrics: "Weakened Immune Systems."

CDC: "Is It Strep Throat?"

Center for Young Women's Health: "Strep Throat."

National Health Service: "Streptococcal Infections."

NY State Department of Health: "Streptococcal Infections."

Seattle Children's Hospital: "Strep Throat Exposure."

WakeMed: "Strep Throat."

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