Most yeast infections are caused by a type of yeast called Candida albicans. Yeast is a fungus that normally lives in the vagina in small numbers. A vaginal yeast infection means that too many yeast cells are growing in the vagina. These infections are very common. When something happens to change the balance of these organisms, yeast can grow too much and cause symptoms. Vaginal yeast infections aren’t considered a sexually transmitted infection (STI). Sexual contact can spread it, but women who aren’t sexually active can also get them. Once you get a yeast infection, you’re also more likely to get another one.
Candida is the scientific name for yeast. It is a fungus that lives almost everywhere, including in your body. Usually, your immune system keeps yeast under control. If you are sick or taking antibiotics, it can multiply and cause an infection.