What are sexually transmitted diseases (STDs)? Sexually transmitted diseases (STDs), or sexually transmitted infections (STIs), are infections that are passed from one person to another through sexual contact. They are usually spread during vaginal, oral, or anal sex.

What are the 4 types of STDs?

1 of 4 curable STIs: chlamydia, gonorrhea, syphilis, and trichomoniasis. More than 500 million people 15–49 years are estimated to have a genital infection with herpes simplex virus (HSV or herpes)