It is possible to contract a sexually transmitted infection (STI) even when in a relationship with only one partner. Monogamy does not inherently provide complete protection from STIs. Understanding the various ways STIs are transmitted, how they can remain undetected, and the history of previous partners helps clarify why such infections can occur within a seemingly closed relationship. This knowledge is important for individuals to make informed decisions about their sexual health and safety.
How Transmission Occurs
Sexually transmitted infections are caused by bacteria, viruses, or parasites. These pathogens spread primarily through the exchange of bodily fluids, such as semen, vaginal fluids, or blood, during sexual contact. Vaginal, anal, and oral sex are common pathways for transmission. Some STIs, including herpes, human papillomavirus (HPV), and syphilis, also spread through direct skin-to-skin contact, even without the exchange of fluids.
The presence of an STI in one partner means the infection can be passed to another during sexual activity. This biological reality means that the number of partners an individual currently has does not singularly determine risk. Instead, it is the nature of the sexual contact and the presence of an infectious agent that facilitates transmission. If one partner is unknowingly infected, the risk of transmission remains.
The Significance of Previous Partners
A key factor in STI transmission within a single-partner relationship often relates to prior sexual experiences of either individual. An infection acquired from a past partner can remain in the body for an extended period, sometimes without causing any noticeable symptoms. This situation is particularly relevant in scenarios where individuals move from one exclusive relationship to another.
Certain STIs are known for their ability to remain dormant or latent for months, years, or even decades. For instance, syphilis can lie dormant for over 30 years without symptoms before progressing to a more severe stage. HIV, if untreated, can exist in a symptom-free chronic phase, also known as clinical latency, for 10 years or more. Similarly, HPV can remain latent for years before symptoms like warts appear or before it contributes to certain cancers. Herpes simplex virus can also be present for years without causing visible outbreaks, yet it can still be transmitted. This extended dormancy means an infection acquired long ago can unexpectedly surface and be transmitted to a current partner.
Understanding Asymptomatic Infections and Testing
A significant challenge in preventing STI transmission lies in the fact that many infections are asymptomatic, meaning they do not produce obvious signs or symptoms. For example, chlamydia is asymptomatic in about 70% to 75% of women and 20% to 40% of men. Gonorrhea is asymptomatic in almost half of infected women and 43% of infected men, with extragenital infections often having no symptoms.
Most people with genital herpes are unaware they have the infection, with estimates ranging from 75% to 90%, and asymptomatic viral shedding is common. HPV also frequently presents without symptoms, with 70% to 90% of cases being asymptomatic. Because of this high prevalence of asymptomatic STIs, individuals cannot rely on symptoms to determine their infection status. The only reliable way to know if an infection is present is through specific STI testing. Regular screening is therefore important for identifying and treating infections that might otherwise go unnoticed, which helps prevent further transmission and potential health complications.
Protecting Yourself in a Relationship
Protecting oneself from STIs within a relationship involves a combination of open communication and appropriate preventative measures. Discussing sexual history with a partner is an important step. This conversation helps individuals understand potential exposures and make informed decisions together about sexual health.
Even within a relationship, the consistent and correct use of barrier methods, such as condoms, can provide a layer of protection against STIs. While condoms significantly reduce the risk of transmission, they do not eliminate it entirely, especially for STIs spread through skin-to-skin contact. Regular STI testing for both partners is a practical approach to maintaining sexual health, even in long-term relationships.