HIV Prevention Community
52.8k Members
Avatar universal

Calculation of odds of getting HIV

Hey people, i found one webpage about the odds of getting HIV from HIV+ partner during unprotected sex.


Is it really so ? Chances are extremely low and it seems like being killed by falling tree is more credible than to get infected with HIV after having straight vaginal sex with the HIV+ girl (odds according to webpage are 1 to 1,000,000).

Ok, data are from 2005, but still... let's assume that after unprotected sex you don't know the partner's HIV status, according to http://www.avert.org/worldstats.htm the average number of HIV infected people in the world is 0.8% (because of high percentage in Africa). Assuming that you have been having unprotected vaginal sex with a girl in North America, your chances of getting HIV  from a single exposure are (1/1,000,000*0.5) 0.0000005%. Actually I can't believe it and I think I'm totally wrong.

What are your thougts ?
26 Responses
Avatar universal
Odds won't tell you a thing about your status.
Avatar universal
Says the "receptive" person is 1:1000000 where as the insertion of Hetero is 1:111,111

How is that possible? Women are more prone to receiving HIV from heterosexual contact then men?
Avatar universal
Yeah, that's right, but we are speaking about the odds, not about the statuses.

MarkCheese, due to several studies it is like that.
Avatar universal
Sorry, not due to several studies, but according to several studies :)
Avatar universal
Although many on this forum preach that Men have a smaller chance of receiving HIV from a positive female then a Women receiving from a positive male.

Or am i mistaken? or is it mixed opinions?
Avatar universal
These odds might not be very precise but they definitely show different levels of risk assosciated with different sexual activities & how risky each of them are compared to one another. CDC estimates are 1:2000 for insertive vaginal sex which ofcourse must be very conservative as they estimate insertive oral sex odds as 1:20000 and receptive oral sex odds as 1:10000 while most experts believe  they are very conservative estimates for oral sex so they cant be conservative in one thing and not others
Avatar universal
This forum does not say either. If you want to discuss odds please see the Dr's on this site.
Avatar universal
I mentioned a mistake in my topic in calculations. 1/1000000 should have been multiplied by 0,005 and not by 0.5, what makes the odds even more friendly, even too friendly, so that information from website probably is wrong but anyway, life is not about odds or calculations, so, wear the rubber, guys, ALWAYS :).
Avatar universal
Use condoms correctly and consistently and you won't have anything to worry about.
Avatar universal
I don't understand those odds... according to that having vaginal and anal sex doesn't offer that much more of a risk than oral sex.

So then why do experts and doctors and sites all over the internet consider vaginal and anal sex as high risk activities and oral sex as very low risk?

Ahh confused now!
Avatar universal
that website is excellent! and by the way although the website has a chart of odds it clearly states that there are so many variables that can affect the odds, anyway I found this on that website:

There are a few basic facts to consider:
Abstinence is the only 100-percent way to avoid HIV and other sexually transmitted infections.
If you have a partner who has tested negative for HIV, does not inject drugs and is having sexual contact only with you, there is minimal risk of being infected with the virus.
Being infected with a sexually transmitted infection (STI) can increase an HIV-positive person's chance of transmitting HIV, just as it can increase an HIV-negative person's chance of acquiring HIV.
An HIV-positive person with a detectable viral load is more infectious-more likely to transmit the virus to somebody else-that an HIV-positive person who is receiving antiretroviral treatment and has an undetectable viral load.
Safer sex practices, including correct and consistent use of condoms for vaginal or anal sex, can reduce the spread of HIV and other STIs.
Getting intoxicated or high on drugs, including alcohol, can impair judgment and cause people to forget to take care of themselves-or their sexual partners.
Safer sex is not just about vaginal, anal or oral intercourse. Masturbation (alone or with someone else), body rubbing, erotic massage and kissing-they're all fun, no-risk activities

source: http://www.poz.com/archive/2005_Aug_348.shtml
Avatar universal
A persons serum viral load has nothing to do with a persons semen viral load.
Avatar universal
That information is completely incorrect.
Avatar universal
the information provided on the POZ website is incorrect or information provided and taken out of context by a forum member?
Avatar universal
You are reading it wrong. It is saying if you are the receptive partner and you are HIV+, there is a 1 in 1,000,000 chance of giving it to the insertive partner.
Avatar universal
well 1 in 1000000 is completely ******** it cant be that high it must be around 1 in 3000 or maybe a little more and the odds in this article about receptive oral is really ridiculous and funny.
The information about safe sex on poz.com is completely accurate. abstinence is 100 percent and then i think protected oral would be around 100 percent too but protected penetrative sex in the long term is not 100 percent safe, practically as there are chances of condom failures and in the long run in real world most people dont use them consistently. I guess protected sex for one time exposure where the condom remained intact and in place is very safe indeed next to zero.
Avatar universal
When a condom is used correctly and consistently they are 100% effective in preventing the transmission of HIV and most STDs.
186166 tn?1385262982

Avatar universal
Sorry teak may i ask you when do you sleep as you are always online :)
Avatar universal
Spot on but how can you know someones status at the time of exposure as there is a window period
Avatar universal
guys, i'm completely new to this topic. Yes, I'm here cause I had unprotected sex with the girl I don't know 1 month ago, even if I know that she is not prostitute and seems like she has a pretty good nature, but still, I'm experiencing paranoia all the time since that night.

So, even, lets say that chances of getting HIV from positive female partner after unprotected vaginal and receiptive oral sex would be 1 to 1000 (worst case), the risk of getting it from a random girl is really low. Almost unreal from 1 exposure.

So, why do people are so worried than and why do there are so many new infected people ?

Probably the 2/3 of all HIV infections should have occurred through regular gay sex and sharing needles, I'm I right ?
Avatar universal
Bud I have friends that contracted HIV on there first exposure and I have friends that never contracted HIV from having sex with an HIV positive person. Now you want to play the game or use condoms correctly and consistently?
Avatar universal
First of all if your partner dont have HIV then you can't be infected. For that you need to ask her status most people dont lie if you cant know her status then you have to test yourself
In industrialised countries yeah these two groups along with people from african origin are at high risk but you wont be able to assess your risk and know your status just by statistics
Avatar universal
Shows how much you know about people that have HIV. Most won't tell the truth about having HIV and the other half doesn't even know their status.
Have an Answer?
Top HIV Answerers
366749 tn?1544698865
Karachi, Pakistan
370181 tn?1428180348
Arlington, WA
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
These tips can help HIV-positive women live a long, healthy life.
Despite the drop in new infections, black women are still at a high risk for HIV, the virus that causes Aids.
What are your HIV treatment options, and how do you choose the right one? Our panel of experts weighs in.
Learn the truth behind 14 common misconceptions about HIV.
Can HIV be transmitted through this sexual activity? Dr. Jose Gonzalez-Garcia answers this commonly-asked question.
A breakthrough study discovers how to reduce risk of HIV transmission by 95 percent.