A partner’s positive test for a sexually transmitted infection (STI) requires immediate action. These infections are transmitted through sexual contact, including vaginal, anal, and oral sex, and sometimes through skin-to-skin contact. While a positive partner means you have been exposed, it does not automatically confirm your own infection status. This high-risk exposure warrants immediate medical consultation and testing.
Assessing the Risk: Why Transmission Isn’t Guaranteed
The risk of contracting an infection after exposure is high, but transmission is not guaranteed. The likelihood of infection is influenced by numerous biological factors. For example, the estimated risk of acquiring chlamydia from an infected partner during a single act of intercourse is approximately 4.5%. For other infections, like trichomoniasis, the risk from a single exposure can range from 60% to 90%.
The body’s natural defense mechanisms may prevent the pathogen from establishing a full infection. The mucosal membranes lining the genital tract serve as a physical barrier against invading microorganisms. A person’s immune system response also plays a role in determining if a transient exposure progresses into a detectable infection. A positive result in one partner means the other partner has had a high-risk exposure, regardless of symptoms.
Variables Determining Infection Status
The specific type of infection is a major factor in transmission probability, differentiating between bacterial and viral pathogens. Bacterial STIs (chlamydia, gonorrhea, and syphilis) can often be cured with antibiotics. Viral STIs (herpes, HPV, and HIV) integrate into host cells and remain in the body, requiring long-term management. Viral infections often have periods of active shedding, making transmission possible even without visible symptoms.
Barrier methods, such as latex condoms or dental dams, significantly reduce the risk of transmission by preventing the exchange of bodily fluids. However, they are less effective against infections transmitted primarily through skin-to-skin contact outside the protected area, such as herpes and HPV. The type of sexual contact also matters, as anal and vaginal intercourse generally carry a higher risk for fluid-borne infections than oral sex.
Physical conditions in the uninfected partner can also increase susceptibility to infection. Pathogens invade the body through microscopic abrasions within the mucosal membranes. Existing inflammation in the genital tract, caused by co-infections like bacterial vaginosis, can compromise the mucosal barrier. This inflammation draws in immune cells that can be targeted by certain pathogens, such as HIV, making acquisition easier.
Essential Next Steps: Testing and Medical Consultation
The primary step is to schedule an immediate consultation with a healthcare provider to discuss the exposure. A provider can assess the type of infection, determine your personal risk level, and decide if immediate treatment or preventative medication is necessary. For certain exposures, like HIV, emergency medication called post-exposure prophylaxis (PEP) may be an option if started within 72 hours of exposure.
Testing must be timed correctly due to the “window period,” which is the time between exposure and when a test can reliably detect the infection. Testing too soon can result in a false-negative result. For common bacterial infections like chlamydia and gonorrhea, testing is often accurate one to two weeks after exposure.
Viral infections, which rely on the immune system to produce detectable antibodies, typically have longer window periods. A healthcare provider will recommend a specific testing schedule, often including a follow-up test after the window period closes, to ensure accuracy.
Typical Window Periods
HIV testing can be reliable as early as 10 to 33 days after exposure using a nucleic acid test, or up to 90 days for certain antibody tests. Syphilis and Hepatitis B may require a wait of up to 90 days for the most accurate antibody results.
While waiting for test results, abstain from sexual activity or consistently use barrier protection to prevent further spread. Open communication with your healthcare provider and any current or future partners is fundamental to managing the situation. Partner notification is an important public health measure to ensure the infection chain is broken.