[Question #8140] HIV risk and test accuracy

48 months ago

Dear Doctor,

Thanks very much for your service on the website. Sorry in advance if my English is not perfect.

I am 24, male and I live in the UK. My exposures are as follows: during the last 8 months, I had encounters with 8 female CSWs in total. Each time I had unprotected oral sex(both ways) and protected vaginal sex. Sometimes I also cum in their mouth. As far as I know, condoms were not broken. The most recent ones are on 30/06, 07/07, and 10/07. All other previous exposures were at least 45 days ago.

I had a 4th generation test on 09/08, which is 30 days after the last exposure, and the result was negative. My questions are:

1. What are my risks of HIV? Do I need to worry?

2. How accurate is my test on 09/08? I noticed that under the latest UK guidance(which I think coincides with the US CDC guidance), the window period is now 45 days rather than 28 days. The evidence they base on is this paper

https://pubmed.ncbi.nlm.nih.gov/25033879/

and you can check the UK guidance here: https://www.bhiva.org/file/5f68c0dd7aefb/HIV-testing-guidelines-2020.pdf

I saw you said on this forum that a test at 30 days is over 99% accurate. However, in the above paper and guidance, the 95 percentile day is 34, which means that the accuracy of a test at 30 days is less than 95%? Why they are different from your comments?

3. Do I need to retest at 45 days or can I just confidently forget about it can continue my life? Do you consider my test result as conclusive, based on my exposures?

Thank you so much for your help!

Edward W. Hook M.D.

48 months ago

Welcome to our forum and thanks for your questions. I’ll be glad to comment. Congratulations as well on your commitment to safe, condom protected sex for your penile vaginal encounters. Please remember that overall the risk of acquiring HIV relates to the likelihood that your partner has untreated HIV, and the sort of exposure you have. In your specific situation most (certainly less than 5% and probably far less) commercial sex workers in the UK do not have HIV. In addition remember that even unprotected penile-genital exposures have a risk of less than one infection per 1000 unprotected encounters on average. In other words 99.9% of unprotected exposures to an infected, untreated partner would not lead to infection. The use of a condom worn throughout the encounter increases the protective affect by close to 100% as long as it does not break. For oral sex, the risk is even lower. Current estimates are the the risk of acquiring HIV through oral sex is less than one infection per 10,000 exposures to infected partners. I would add to that that I have never seen or heard of a person who acquired HIV through either cunnilingus or receipt of oral sex. Ejaculation makes no difference in risk. From this background information, you can see that your risk for acquisition of HIV through the activities you describe it is very, very low. Now onto your specific questions.

1. Is outlined above, you are risks for HIV are very, very low. Your testing validates this.

2. Official guidelines and recommendations tend to be conservative. As you know from looking at our forum, we agree with the guidance that testing at 42 to 45 days following exposure is absolutely conclusive. From study of the literature over the years, I continue to estimate that results of tests taken after four weeks are 99% conclusive. While I am sure that somewhere there are a handful of patients who may have converted their test in the interval between 28 and 45 days, I have never seen or heard of such a patient.

3. You need to retest at 45 days depends on your level of concern and what is needed to feel comfortable. From your descriptions and the test results you have provided thus far were I you, I would not bother to test at 45 days and would move forward without continuing concern.

I hope that the information and perspective that I have provided is helpful. As you know, if any part of this reply is unclear or you have further questions please don’t hesitate do use your update to follow up questions for clarification. EWH

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48 months ago

Thank you very much for your reply! Just some follow-up questions.

1. What do you mean by very, very low? I saw some other words are also used on this forum such as virtually zero, zero for all practical reasons, etc. Are there any differences between them?

2. Should I expect a negative result if I choose to get tested again at 45 days? I am very anxious.

Edward W. Hook M.D.

48 months ago

Please understand that I am sometimes tired of saying the same thing again and again and again. Your risk of having a future positive test related to the exposures you described can be characterized as “very very low”, “virtually zero”, or “zero for all practical purposes”. It is certainly too low to provide a practical, meaningful number or proportion on..

I am quite confident that when you retire at 45 days the result will once again show that you have not been infected with HIV. I do find myself wondering why you are now feeling so anxious after having behaved in much the same way for at least the past eight months with a different CSW partners.

Hope this helps. Please don’t worry. EWH

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48 months ago

Thanks very much for your reply! The reason is that I plan to change my lifestyle and start a new relationship so I want to make sure I am free of Hiv risks. I had a 4th generation test again on day 42 and the result is negative. Now I will continue my life with no worries. Thanks again for your help!

Edward W. Hook M.D.

48 months ago

Thanks for your follow-up. Your day 42 results are entirely conclusive. I wish the best going forward. EWH---