How Long Is Strep Throat Contagious?

Strep Throat Basics


Strep throat is caused by the bacteria streptococcus pyogenes. It is considered GAS, which stands for Group A Streptococcus infection, and you can be contagious for a 2- to 5-day period before you even start to experience symptoms. During this time, you will probably unwittingly share your germs with someone else. Once you start to have symptoms and suspect you may have strep throat, you are contagious and should start taking precautions not to infect those around you. If you’re not sure whether you have strep, you may wish to read:

  • Strep Throat Symptoms
  • Is Your Sore Throat Strep?

Do I Need Antibiotics?


Strep throat is most common in children between 5 to 15 years old, and only makes up 5-10% of sore throat cases in adults. This is why your doctor will not just start giving you antibiotics right away. It is important to help prevent development of “super bugs”, or antibiotic resistant bacteria, that your doctor is sure you need antibiotics.

To test for strep throat, your doctor will need to perform a strep test.

If your strep test is negative and your doctor suspects a viral infection, you will not need antibiotics. However if you test positive for strep throat, you will be prescribed Penicillin V, Amoxicillin or another antibiotic that is known to be effective.

How Long Will I Be Contagious?


If you are diagnosed with strep, you will stop being contagious approximately 24 hours after starting an antibiotic. Antibiotics should help alleviate your symptoms within one or two days, although in some people the symptoms may last up to a week. (Without treatment, strep throat generally resolves on its own in about a week.) If you don’t have any reduction in fever or other symptoms within 48 hours of starting antibiotics, contact your physician.

Studies have shown that if you are on an antibiotic and you do not have a fever the night before returning to school or work, you will not be contagious. Identification of fever the night before is important in identifying whether or not you will likely spread strep throat to others around you.