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 Jersey,
If you’re partner is on medication and has an undetectable viral load you won’t contract HIV. Please see here for more info:
https://i-base.info/qa/what-are-the-most-asked-questions
If they aren’t on meds then you risk being infected. This is if you have sex without using a condom.
I’ve fallen in love with someone who is positive. I don’t want to make him feel uncomfortable. Will I be OK?
Hi Hansie,
Please see Q5 here:
https://i-base.info/qa/what-are-the-most-asked-questions
Why is it that I’m positive, but the girl I sleep with isn’t?
Hi Franchise,
You can only get HIV from someone who is positive. For more info, please see Q1 here:
https://i-base.info/qa/what-are-the-most-asked-questions
Hi Lisa
I really like this information your sharing. I’m really learning a lot I didn’t no about.
The question i have is can HIV manufacturer on it own without contacting it from someone who already has the virus. Like for example if a person who is HIV- sleep with multiple partner ( like 5 or 8) who are also HIV-can one end up developing the virus like that. I think what I’m trying to ask is can one develop or manufacturer HIV or it can only gotten from some one who is HIV +?
Hi Sriman,
Please see Q’s 1 and 9 here:
https://i-base.info/qa/what-are-the-most-asked-questions
My condom was broken in middle of the sex and my partner has hiv.please tell me my chances of contracting hiv.
Hi Gugu,
If you’re on treatment and your viral load is undetectable, the risk of transmission is close to zero. Please see here for more info:
https://i-base.info/qa-on-the-partner-study/
I am a virgin and i was born HIV Positive now i want to have sex will my boyfriend be infected if we do unprotected sex?