What are STIs?Sexually Transmitted Diseases are a set of infections that are passed from one person to another during sex. It is mainly caused by bacteria or viruses. These diseases can be transmitted through sexual contact, oral sex, and sharing items like towels, forks, and toothbrushes with people who have an infection. Most sexually transmitted diseases can last for weeks without treatment or show no symptoms at all. One way to prevent contracting STIs is abstinence, but it’s not 100% effect