As background, I had unprotected sex with a man (I am female) back in May of 2023. I did not have sex again until last month, with a different man, where we used a condom about 50% of the time. In the past year and a half, I’ve only had sex with these two men, one time each.

Flash forward to this past Monday, I test positive for chlamydia. I did not have any symptoms whatsoever. This is the first time I’ve gotten tested for STDs since March 2023. My partner from last month went and got tested, and he tested negative. My doctors office said I likely got it last month, not back in May of 2023, even though his test came back negative. 

My question is, is it possible for my last partner to have gotten a false negative? That would mean I contracted it from him rather than in May 2023. I’m really worried I’ve had chlamydia for over a year. Additionally, is it possible to go 15 months without ever having symptoms of chlamydia or HIV? With this positive chlamydia test, I’m now worried I’ve been walking around with HIV for over a year. Thank you so much.

This is a common situation -- diagnosis of chlamydia or other STI but no apparent infection in one or more partners who would expect to test positive. There are a few likely explanations. 

Chlamydia can persist for a year or more -- even up to 3-4 years -- with no symptoms at all. However, most infections are cleared by the immune system within a few months, which undoubtedly is why your doctor suspects you were infected recently. And that's definitely possible as well. The usual test in males -- a nucleic acid amplification test (NAAT) on urine -- misses up to 5% or maybe sometimes 10% of infections. It's also possible your partner had it but underwent spontaneous cure before being tested. And are you sure he didn't suspect his infection and get treated before being tested? Or maybe took an antibiotic for another reason, not knowing he had chlamydia?

As for HIV, of course anybody with any newly diagnosed STI should also be tested for HIV. However, HIV remains extremely rare in most sexually active women. You should be tested for it -- probably already done? -- and can expect a negative result.

At this point, the most important thing is that both you and your recent partner need treatment. I hope you were prescribed doxycycline for a week; the formerly recommended treatment with single dose azithromycin is now known to not be reliable, especially in women. Your recent partner should also be treated regardless of his negative test result.

I hope these comments are helpful. Let me know if anything isn't clear.

HHH, MD