How are sexually transmitted infections (STIs) most commonly transmitted?

Sexually transmitted infections (STIs) are primarily transmitted through sexual contact, which includes various forms of sexual activity such as vaginal, anal, and oral sex. During these activities, bodily fluids such as semen, vaginal secretions, and blood can be exchanged, providing a pathway for pathogens to enter a person's body and establish an infection. This form of transmission is a critical focus in sexual health education to promote safe practices and reduce the spread of STIs.

While options like sharing food and drinks, skin-to-skin contact without sexual interaction, and airborne transmission may be associated with other types of infections or illnesses, they do not represent the common modes of transmission for STIs. Food and drink sharing typically does not involve the exchange of bodily fluids necessary for STI transmission. Skin-to-skin contact can transmit some infections (like herpes or HPV), but in the context of STIs broadly, sexual contact encompasses a wider range of transmission risks and is thus considered the most common and significant pathway. Airborne transmission is mainly associated with respiratory pathogens and is not a transmission route for STIs.