It’s a common assumption: if both partners in a monogamous relationship are tested and come back negative for sexually transmitted infections (STIs), then the risk is eliminated. However, the reality of STI transmission is more nuanced. Many couples find themselves asking, “Can you get an STD if both partners have no STDs?”. The answer, while reassuring in many ways, requires a deeper understanding of how STIs work, testing limitations, and the complexities of sexual health.
While the likelihood of contracting an STI in a mutually monogamous relationship where both partners have been recently and thoroughly tested is low, it’s not zero. This article, as your expert partner support at income-partners.net, will explore the various ways STIs can still occur even when both partners believe they are STI-free. Understanding these possibilities is crucial for maintaining sexual health and ensuring peace of mind in your relationship.
Reasons Why STIs Can Occur Even When Both Partners Are “Clear”
Several factors can contribute to STI transmission even when both partners believe they are free from infections. These reasons often involve the limitations of testing, the nature of STIs themselves, and even the effects of other medical treatments.
Treatment Failure: When STIs Linger
Sometimes, a previous STI infection might not be fully eradicated by treatment. Syphilis is a prime example. This bacterial infection progresses through stages, and if treatment isn’t effective at any stage, the infection can persist silently. It can then become apparent much later, either through severe symptoms or when a partner becomes infected.
Failure of treatment can occur for several reasons:
- Inadequate treatment regimen: The prescribed medication or dosage might not be sufficient to fully clear the infection.
- Antibiotic resistance: This is increasingly common with bacterial STIs like chlamydia and gonorrhea. If antibiotics are not taken as prescribed—completing the full course is vital—bacteria can develop resistance, making the infection harder to treat in the future.
Incomplete STI Screening: Missing the Full Picture
STI screening is not always comprehensive. There are over 20 different STIs, each requiring specific tests for diagnosis. Routine STI screenings often focus on the most common STIs like chlamydia, gonorrhea, syphilis, and HIV. Testing for less common STIs might only be conducted for individuals in high-risk groups.
Moreover, testing might not be exhaustive in terms of body sites. A healthcare provider might only perform swab tests on genitals, potentially missing infections in the mouth, throat, or anus. Oral STIs, for instance, can be transmitted through oral sex and remain undiagnosed if these areas are not tested. Therefore, an STI can be present and transmitted even if standard genital testing comes back negative.
False-Negative Tests: When Tests Give Misleading Results
STI tests, while generally reliable, are not infallible. False-negative results—where a test indicates no infection when one is actually present—can occur. This is rarely due to faulty tests but more often because of the timing of the test in relation to potential exposure.
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Many STI tests detect antibodies, immune proteins produced by the body in response to infection. During the incubation period—the time between infection and when a test can detect it—antibody levels might be too low to be detected. Testing during this “window period” can lead to a false negative, potentially resulting in unknowingly transmitting the STI to a partner. This is why healthcare providers often inquire about potential exposure dates and might recommend repeat testing after a certain period.
Refer to the table below for typical incubation periods for common STIs to understand testing timelines better:
| STI | Incubation Period |
|---|---|
| Genital herpes | 2 to 14 days |
| Chlamydia | 14 to 21 days |
| Trichomoniasis | 5 to 28 days |
| Gonorrhea | 5 to 30 days |
| Hepatitis B | 28 to 42 days |
| Syphilis | 10 to 90 days |
| HIV | 2 weeks to years |
Asymptomatic Infections: Silent Spreaders
Many STIs, including chlamydia, gonorrhea, herpes, HIV, and HPV, can be asymptomatic, meaning infected individuals show no symptoms. This is particularly common in women with chlamydia, where up to 75% experience no symptoms. These asymptomatic infections can still be transmitted to partners without either person being aware of the infection.
Herpes is a notable example, as most people with herpes are asymptomatic and may never experience outbreaks. The virus can remain dormant and reactivate periodically, leading to viral shedding and potential transmission even without visible symptoms. Sometimes, a herpes flare-up can be as subtle as what appears to be an ingrown hair, easily overlooked.
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Accidental Cure: Unintentional STI Treatment
Paradoxically, an STI can be unknowingly “cured” if a partner takes antibiotics for a different infection. Many common antibiotics prescribed for conditions like strep throat or ear infections can also treat bacterial STIs such as chlamydia and gonorrhea.
If one partner unknowingly has an STI and takes antibiotics for another reason, the STI might be cleared without them realizing they ever had it. This can lead to discordant test results where one partner tests positive for an STI and the other tests negative, creating confusion and potentially misattributing infidelity.
How STIs Are Not Typically Transmitted
It’s important to clarify that STIs are generally transmitted through intimate sexual contact, primarily vaginal, anal, or oral sex. They are not typically spread through casual contact such as:
- Toilet seats
- Hugging
- Handshaking
- Mosquitoes
- Shared utensils
- Dental procedures (with proper sterilization)
- Towels and bedding
- Swimming pools
While extremely rare, fomite transmission—transmission via objects—is theoretically possible. If bodily fluids containing an STI virus or bacteria contaminate surfaces, and someone comes into contact with these fluids and then touches their mouth, eyes, or genitals, transmission could occur. However, this is highly unlikely in practice. A more plausible, although still rare, scenario is hand-to-eye transmission of gonorrhea or transmission via shared sex toys if not properly cleaned.
Non-Sexual STI Transmission
Besides sexual contact, STIs can be transmitted non-sexually in certain situations. The most significant is mother-to-child transmission during birth. Pregnant individuals should discuss STI risks and necessary testing with their healthcare provider to protect their babies.
Certain STIs like chlamydia, gonorrhea, and syphilis can also infect the eyes, although this is uncommon. Hand-to-eye transmission of these infections is possible. Additionally, herpes simplex virus type 1 (HSV-1), which causes cold sores, can be transmitted non-sexually through activities like sharing drinks. Oral sex can then transmit herpes to a partner if a person has an active cold sore.
Summary: Navigating STI Risks in Relationships
It is indeed possible for STIs to occur in seemingly monogamous relationships, even when both partners initially test negative. Factors like treatment failures, incomplete screenings, false negatives, asymptomatic infections, and even accidental cures can play a role.
If you and your partner are in a monogamous relationship and an STI is diagnosed, it’s essential for both of you to get tested and treated appropriately. Regular STI screenings are vital for maintaining sexual health, especially when starting a new monogamous relationship or if either partner has had prior sexual activity. Understanding the nuances of STI transmission and practicing open communication with your partner and healthcare provider are key to navigating these complexities.
A Word From Verywell
A positive STI test can raise questions and concerns within a relationship, but it doesn’t automatically indicate infidelity. Understanding the various ways STIs can be transmitted, even in monogamous settings, is crucial. Regular STI testing, ideally before entering a new monogamous relationship and periodically thereafter, is a responsible step in protecting your health and your partner’s health. Open communication and proactive healthcare are the cornerstones of a healthy and informed sexual relationship.
— CORDELIA NWANKWO, MD, MEDICAL EXPERT BOARD
