Strep throat is the most common of bacterial infections that cause sore throat. It accounts for about 5% - 15% of all sore throats in adults and 20% - 30% in children.
It's called "strep" throat because the bacterium that causes it belongs to the class known as group A streptococcus (GAS). The initials GAS are sometimes used, and doctors may talk about a GAS throat infection. Although strep throat can occur any time during the year, late winter and early spring are considered to be peak seasons for strep throat infections.
Sore throat is one of the leading complaints that bring people to the doctor's office, and about 40%-50% of sore throats are treated with antibiotics. However, fewer than half of the people given antibiotics actually have bacterial infections. Most of the rest have viral infections that are not affected by antibiotics.
When used appropriately, antibiotics are very helpful in fighting infection. However, antibiotics used inappropriately can be bad for you, killing harmless bacteria that may be keeping dangerous bacteria out of your intestines. It is important to learn about appropriate (and unnecessary) antibiotic use, and this includes not pressing a doctor for antibiotics when the doctor says they aren't needed.