Question
if you have sex with someone who has HIV are you guaranteed to catch HIV?
10 January 2018. Related: All topics, HIV transmission.
Answer
No, the opposite is true, HIV is a difficult virus to catch.
The actual risk in any single situation probably vary from zero (no risk) to to less than 1 in 20,000 (0.05% risk per exposure) to 1 in 10 (10% risk per exposure). This will depend on many things, including: the viral load of the HIV positive partner, the type of sex, whether you use a condom, if there are STIs, genetics etc).
The risk is zero if the positive partner is on treatment (ART) with an undetectable viral load. An undetectable viral load makes HIV untransmittable. (See: The evidence for U=U).
Low risks (1 in 5,000) include oral sex generally (not in early infection), or perhaps the risk of a condom breaking.
High risk – perhaps 1 in 100 to 300 – is estimated from vaginal or anal intercourse without using a condom (not accounting for viral load), or for oral sex with someone who has recently been infected.
Highest risk would involve blood to blood contact with someone who has a high viral load.
Although HIV is not an easy virus to catch – it does only takes one exposure for infection to occur in any risk setting other than zero. There is probably zero risk if the positive partner has undetectable viral load, if the negative partner uses PrEP or when condoms are used properly.
Many HIV positive people have sex with HIV negative people, including in long-term relationships, without the negative person catching HIV.
See also the info and links from this page.
This question was updated in January 2018 from an original answer posted in May 2008. i-Base no longer answers individual questions about HIV transmission and risk. (See: Question 1, 5, 6 and 9 at this link).
Comments to this thread are now closed.
Hi Nichollus.
You could take PEP. For more info on what PEP is, and when its most effective see the following:
http://i-base.info/qa/5255
What is it that u can take after sleeping with a person whom u r not sure of the status and after how long you must take just to be on a safe side
Hi tafadzwa,
Please see question 5 here:
http://i-base.info/qa/7308
hie I have been sleeping with an infected person for 6 months without condom but when I get tested I was negative. …can you tell me I can be like that for the rest of my life
Hi Thomie, please see question 1, 5 and 9 at this link:
http://i-base.info/guides/12423
I’ve been involved in unprotected sex with an HIV positive partner and got infected with STI .and the following month I went to the clinic where I tested negative for HIV. I just wanted to understand how possible it is.
Hi KD, please see this link for information about risk:
http://i-base.info/qa/factsheets/hiv-transmission-and-testing
Accidentally , got off condom and I had intercrouse with her almost 2 minutes without Condom . I Donot know her status but is there any chances to get infected if she is HIV positive. Immediately I washed my private part with soap.
Hi Kevin, the ARTNER study shows you have little to worry about in terms of catching HIV because your girl friend is on treatment.
http://i-base.info/qa-on-the-partner-study
pls i was having sex with my girl friend for good 9 math I don’t know she was taking tablet and one day i fund them in her handbag she tell me she was on medication form 2010 to 2016 and we started having sex with no condom from November 2015 to June 2016 befor I found out