[Question #2075] HIV/STD CONCERN

Avatar photo
84 months ago
Hi there, 

I have been with my girlfriend for exactly 2 years, we regularly partake in unprotected sex, oral and vaginal. 

Today, she has informed me she has tested positive for chlamydia, swab test via a private STD clinic within the UK. When we first got together back in 2015, she was tested then and claimed to be negative for everything. Its only recently she had another test done at a private clinic and tested positive for chlamydia. 

Approximately, 8 years ago, I engaged in unprotected anal, vaginal and oral sex with a sex worker within a brothel in the Czech Republic. Once I returned to the UK, I was tested 6 weeks and 12 weeks (84 days). I was negative for all STD's and HIV. I was tested for free via a NHS Gum Clinic within the UK. 

Back in 2014, I engaged in unprotected oral sex, receiving oral from a verified white British escort. She informed me she is regularly tested for all STD's due to the nature of her work. I NEVER got tested after this encounter as I believed oral carried a little to no risk for STD's. 

Apart from these two encounters I have only ever been sexual with my current partner. 

My questions are: 

1) Despite negative STD's and HIV tests back in 2009 at 6 weeks and 12. Is there any way I have been infected all this time and the tests done at the time failed to pick up any infection? 

2) Can you obtain Chlamydia from receiving oral sex? 

3) What are the possibilities my partner had a  false positive? The clinic stated the test is 99.9% accurate. 

4) I plan to get tested for Chlamydia however will HIV testing be necessary after a 3 month negative back in 2009?   

My girlfriend has had two previous partners in the past and she has informed me she has had safe sex with them. Having said that, her partners were long term. My encounters have been single encounters, one back in 2009 and one in 2014. 

Any answers would be massively appreciated right now, I feel absolutely confused. 

Kind regards, 


Avatar photo
H. Hunter Handsfield, MD
84 months ago
Welcome to the forum. Thanks for your question.

Considering all situations like this, by far the most common explanation is one partner recently became infected from someone else. So the first thing is to have a senstive, caring, non-accusatory heart to heart conversation about this possibility (if you haven't already done so). And in all frankness, I have to ask why your partner visited the private STD clinic, unless she suspected she might be at risk. But once you are reassured that's not the case, there are some other potential explanations. The rest of this reply assumes that neither of you has had other partners since your relationship started two years ago.

In general, chlamydia is cleared by the immune system, without antibiotic treatment, within a few months, but in rare cases it may persist a year or more. Relatively recent research suggests that chlamydia may sometimes persist in the gastrointestinal tract, then make its way into the genital tract from the rectum. (You can imagine why female anatomy may permit this more commonly than in men.) So there is a possibility your partner was infected sometime before your relationships began, it was never detected, but the infection persisted in her GI tract -- and her current positive result therefore is not due to a newly acquired infection. 

Another possibility may be that her positive result is false. The most commonly used chlamydia methods are nucleci acid amplification tests (NAATs), but a less expensive DNA probe test sometimes is still used in some clinics. The probe tests occasionally give false positive results, but NAATs almost never do. So your partner might check with the clinic and see exactly what test was done. If it was a DNA probe test, then I would bet her test was false.

Those comments address most of your questions, but to be explicit:

1) While false negative results can occur, they are uncommon; and with two negative tests 6 weeks apart, it is exceedingly unlikely you had chlamydia back in 2009. And even if you did, there is no realistic chance it persisted for more than a few months after that.

2) Chlamydia is not easily transmitted by oral sex, mostly because oral chlamydia is quite uncommon. In any case, even if you were infected by oral sex back in 2014, it would be very unlikely to persist long enough to infect your current partner.

3) See above about false positive test results. The 99.9% figure given by the clinic is accurate for NAAT, but the chance of false pos is somewhat higher if she had a probe test.

4) Given your sexual history, I would be extremely surprised if either you or your partner has HIV, regardless of the chlamydia. My guess is your partner had an HIV test at the private clinic. Almost all STD knowledgeable doctors or clinics would automatically test for HIV whenever any STD testing is done. If she was HIV negative, you can be confident you are not infected. That said, when you are tested for chlamydia, you can expect an HIV test at the same time. I'm confident it would be negative.

Bottom line:  You may never have a clear explanation, and I would encourage you not to get too worked up by it. The most important thing at this point is that both of you be treated. Presumably plans for this are underway, if not yet done.

I hope these comments have been helpful, but let me know if anything isn't clear.

Best wishes--  HHH, MD

Avatar photo
84 months ago
Dear Dr Handsfield

Thank you for your recent response. It was greatly appreciated and very helpful. 

I did ask my partner why she visited a private clinic for an STD screening. She informed me she always has a burning/weird sensation after we have sex. She stated it was purely for piece of mind. 

I can confirm  we are both committed and have only ever been sexual with each other for the past two years. None of us have had any other sexual encounters or relationships within the two years. 

My partner was indeed tested for HIV and all other STD's. She  was negative for all apart from Chlamydia. 

My original message was created 24 hours ago, saved and sent to you. I can confirm since I have visited a NHS GUM Clinic in the UK for a Chlamydia and HIV test.  

The clinic informed me they have used a 4th generation combined p24 antigen test for HIV testing. 

I provided a urine sample for the Chlamydia, however soon after I provided my sample, the clinic didn't want to take any risks so they provided me with 4 pills of Azithromycin. I took them as soon as I got home. My partner also was given the same, she also took hers the same time as myself.

Your response in terms of the Chlamydia information does make sense. I have asked my partner to ask the clinic further which test they carried out. She will be pursing this further. 

The only really outstanding questions I have are:

1) How confident can I really be that I will be HIV negative? This has caused me 2 sleepless nights thus far, the clinic told me I am at very low risk for this but they do the test as standard as you mentioned. I was tested after my potential exposure back in 2009 at 6 weeks and 12 weeks with negative results, this was a full  STD screening. I have never had vaginal sex from 2009 to 2015. My first vaginal intercourse was with my current partner after my encounter in 2009.

2) Is there a potential that this whole situation may cause issues for me and my partner to have children in the near future.

3) How effective is Azithromycin in clearing Chlamydia?  

4) Assuming I prove to be HIV negative and have now taken Azithromycin. Could myself and my partner return to unprotected sex in a few weeks?

5) Would this HIV test be fully conclusive or would I need to test again?

Thank you in advance, 

Kind regards


Avatar photo
H. Hunter Handsfield, MD
84 months ago
The clinic followed standard recommendations. The partners of people with treatable STDs, like chlamydia, should be treated without waiting for test results. You would require treatement even if your own test were negative (which it may well be), so there's no reason to wait on treatment.

1,5) If your and your partner's sexual histories are accurate, you can be 100% sure you don't have HIV and the negative test will be conclusive.
2) There is little if any risk that your partner's chlamydia or anything else about this situation would cause any problems in conception or raising healthy children.
3) Azithromycin is about 96-98% effective. However, it is less effective against rectal or gastrointestinal infection -- which, as discussed above, conceivably is how all this developed. It would be a good idea for both of you to be retested in 3-4 months; if still negative then, no worries.
4) Standard advice is to not have sex for a week, but this is largely to protect new partners, or a current partner who hasn't yet been treated. The two of you could safely have sex right now. For sure there is no need to wait "a few weeks".

Avatar photo
84 months ago
Hi Dr Hansfield,

I have been away on a holiday with my partner and discussed this whole situation with her. 

She has informed me all her previously sexual encounters have  been protected and she has only been with myself for last 2 years. 

Having said that, she did mention she had brief protected anal sex with a partner more than 2 years ago. 

Can rectal or gastrointestinal infection only be caused by unprotected anal sex?  If not, then what causes this?

The Chlamydia test she had was a swab test not a urine test. She is yet to ask the clinic for exact confirmation, for example, if it was a DNA probe test or NAAT. Would a swab test be likely to cause a false positive over a urine sample?

I am currently awaiting my Chlamydia and HIV results.  As you are aware, me and my partner both took Azithromycin after finding out my partner had tested positive for Chlamydia. 24 hours later we have engaged in unprotected sex, will this be ok?

Sorry to keep going on, I just wanted to be 100% sure myself and my partner are OK in terms of all STD's as this situation has been frightening. 

From reviewing the whole situation, I really do think she had a false positive. However, the clinic within the UK believe the test is accurate and she definitely had/has chlamydia.  Does this sound a possibility?

Kind regards, 


Avatar photo
H. Hunter Handsfield, MD
84 months ago
OK, a few final replies and other thoughts.

That your partner's other sexual experiences all were condom protected reduced her risk for chlamydia and other STDs but didn't eliminate it. Condoms aren't perfect and are not always used correctly, and there is a real possibility she acquired chlamydia somewhere along the line. This is more likely than a false positive result, especially if she was tested by NAAT.

The theory about gastrointestintal colonization with chlamydia, and the GI tract serving as a harder-to-cure long term reservoir, is just that, a theory. This clearly happens in several animals with their own chlamydia species, but it has not been proved in humans and some chlamydia experts are doubtful. Personally, I think it's a good possibility, and we know for sure that rectal chlamydial infections respond less well to azithromycin than genital infections do. But if this happens, it doesn't require anal sex. Genital chlamydia easily reaches the anus in women; and other cases may originate orally, either by oral sex or by oral infection from one's own genital infection, e.g. from a lapse in toilet hygiene.

Swab testing, not urine, is the preferred method for NAAT in women. However, probe testing isn't done on urine at all -- so the fact of a swab leaves open the possibility of a DNA probe test, with its slight possibility of a false positive result.

There was probably no higher risk of treatment failure or other problem from having sex only 24 hr after azithro. Normally a week is recommended, but that's most important for new or untreated partners.

A final comment for you to discuss with the GUM clinic and/or your partner's private clinic. (Was that London's Freedom Health Clinic? By reputation and my knowledge of the medical director, the care is highly expert.) Many chlamydia experts would use doxycycline rather than azithromycin in couples like you. It's slightly more effective than azithro, with virtually no treatment failures for genital infection, vs. 2-3% for azithro; and for sure doxy is more effecrtive than azithro against rectal infection (0% vs 10-20% failure) and perhaps against the possible GI reservoir.

As for your final conclusion about a false positive test, I am not so confident in that, especially if she was tested by NAAT. But as I said before, you're probably never going to know for sure and I would urge you not to spend any more time or energy trying to figure it out.

That completes the two follow-up questions and replies included with each question and so concludes this thread. Best wishes to you and your partner.