What’s the Difference?
The only difference between a sexually transmitted disease (STD) and a sexually transmitted infection (STI) is in the meaning of the terms themselves:
STDs, or sexually transmitted diseases, are very common—millions of new cases occur every year in the U.S. STDs are passed onto individuals through sexual activity including vaginal, oral, and anal sex.
STIs, or sexually transmitted infections, is a newer term that many healthcare professionals use to replace STDs. Why? The word “disease” in STD suggests a clear medical problem with obvious signs and symptoms. But several common STDs have no signs or symptoms in the majority of people infected by them. For example, you can be infected by sexually transmitted bacteria like chlamydia or herpes but not have a “disease” with symptoms.
The term STD is still used frequently in the healthcare industry, so note that STD/STI are essentially referring to the same thing.