Mr Natural

Studies showing Het transmission of HIV?

21 posts in this topic

Hi there.

Can anyone give me links to studies about heterosexual transmission of HIV between non-drug users, without additional complicating factors like cuts? Rates of infection, or scientific opinion on risk.

I'm not trying to start anything or bring up the bareback debate, I just want to find out what evidence is there, and thought that people in the trade might know.

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Thanks for the link. I'm really after any studies about HIV heterosexual transmission that clearly show transmission with no complicating factors, e.g. cuts and lesions, anal sex, drug use.

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Hi there.

Can anyone give me links to studies about heterosexual transmission of HIV between non-drug users, without additional complicating factors like cuts? Rates of infection, or scientific opinion on risk.

Why don't you just hit Google to find out for yourself? :D

Here is the start..and then filter away the information which you are not interested in.

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I have googled obviously, but can't find any actual studies about transmission with no other risk factors.

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The playboy adviser carried an article about something similar about 10 years ago: the results were a little counter to many people's prejudices. A 'diagonal' heterosexual group where one was HIV and the other wasn't had unprotected vaginal sex only, no anal whatsoever. These were usually married or long termers and both knew the situation and accepted the risk as they loved their partner. The transmission rate was incredibly low.

A diagonal group that had only protected sex ( but which included protected anal ) had comparatively high transmission rates.

I can't remember which issue it was in, but if you are serious enough to spend some money on this, you could always join the online magazine and search their adviser archive - lots of other good stuff in there that would be worth a short term subscription ( and I don't mean the pictures :D )

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I have googled obviously, but can't find any actual studies about transmission with no other risk factors.

Because.............IMO it's at such a low level that research/studies are not necessary.

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I always thought it was 1/1000 for men and 1/100 for women.

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According to wikipedia it's 1/2000 for men and 1/1000 for women. However, the transmissions in those studies are not clearly without complications.

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The figures I quoted are the very early days ones. Don't forget if you have any other infections the chance of HIV infection increases dramatically.

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According to wikipedia it's 1/2000 for men and 1/1000 for women. However, the transmissions in those studies are not clearly without complications.

To show how unreliable statistics are it should be remembered there are documented cases of one incidence of hetrosexual intercourse leading to a participant contracting the virus.

I also remember reading about a guy infecting 3 different women. Id guess he would have been hard pressed to have sex with each of them 2000 times!

Maybe the chances of passing the virus also depend on how virulant the virus may become in a certain individual.

I doubt the virus leaves a body in the same state it enters?

Each of our bodies are similar but a seperate enviroment for nastys. Whats to say it doesnt develope into a more or less infective state depending on differing enviromantal factors within a host. Isnt that what evolution is about?

We are all similar but makedly different, Infection chances also depends on the person too.

I guess the answer is not to use statistics to gamble on your chances, but to weigh the dice in your favour by taking all the precautions and not leaving your exposure to infection in the hands of chance and statistics.

The chanaces of infection are different for us all. There is no overall picture just statistics.

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it is interesting because according to wikipedia the ratio of risk within

oral and intercourse is only 1 to 10 (considering the amount of OWO offered I would have guessed a much higher number).

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Hi there.

Can anyone give me links to studies about heterosexual transmission of HIV between non-drug users, without additional complicating factors like cuts? Rates of infection, or scientific opinion on risk.

I'm not trying to start anything or bring up the bareback debate, I just want to find out what evidence is there, and thought that people in the trade might know.

It depends on a whole host of factors. If a person has just recently become infected they're more contagious than someone who's had it a while; if someone is aware they're HIV+ and undergoing treatment then they're less likely to pass it on than someone who's not being treated. Obviously it's largely impossible to know for certain whether someone had a cut or lesion on their penis or inside their vagina when they caught it. There have been numerous cases of people (usually men) who have had sex with HIV+ partners for years and years and come away HIV negative. But equally there are cases of people catching it immediately. There was even a case I read of where a gay man was told he had the virus and assumed he'd caught it from his HIV+ partner despite their use of condoms, obviously at this point they stopped using them and carried on with their lives for almost a year I think; at which point they found the original test was a false positive and the guy was negative. And had remained so for the proceeding year despite practising unsafe anal sex with an HIV+ man. Obviously this was probably in part due to the factors I mentioned earlier - the partner had had the virus a while, knew he had it and was undergoing treatment...but then they were having anal sex so he's still a very lucky boy. For men it's more difficult to catch as there's no obvious route for the virus to follow to get into the body without complicating factors as you put it, and as soon as sex finishes the risk is over. For women obviously the virus is getting in the body via the semen which is left in the body after sex, although virus loads are quite low in semen.

So all in all it's a bit of a lottery. For men unless you're having sex with an HIV+ partner regularly you'd be statistically unlucky to catch it from vaginal sex. But there's always going to be people who are going to get it first time. Also I've just remembered that if you're circumcised the risk is lower (for female to male transmission).

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It depends on a whole host of factors. If a person has just recently become infected they're more contagious than someone who's had it a while; if someone is aware they're HIV+ and undergoing treatment then they're less likely to pass it on than someone who's not being treated. Obviously it's largely impossible to know for certain whether someone had a cut or lesion on their penis or inside their vagina when they caught it. There have been numerous cases of people (usually men) who have had sex with HIV+ partners for years and years and come away HIV negative. But equally there are cases of people catching it immediately. There was even a case I read of where a gay man was told he had the virus and assumed he'd caught it from his HIV+ partner despite their use of condoms, obviously at this point they stopped using them and carried on with their lives for almost a year I think; at which point they found the original test was a false positive and the guy was negative. And had remained so for the proceeding year despite practising unsafe anal sex with an HIV+ man. Obviously this was probably in part due to the factors I mentioned earlier - the partner had had the virus a while, knew he had it and was undergoing treatment...but then they were having anal sex so he's still a very lucky boy. For men it's more difficult to catch as there's no obvious route for the virus to follow to get into the body without complicating factors as you put it, and as soon as sex finishes the risk is over. For women obviously the virus is getting in the body via the semen which is left in the body after sex, although virus loads are quite low in semen.

So all in all it's a bit of a lottery. For men unless you're having sex with an HIV+ partner regularly you'd be statistically unlucky to catch it from vaginal sex. But there's always going to be people who are going to get it first time. Also I've just remembered that if you're circumcised the risk is lower (for female to male transmission).

Oh and I've just remembered that for anal sex the much higher risk is for the person receiving the anal sex. If you're giving anal sex the risk is only marginally higher than vaginal sex, as there's still no obvious route for the virus to get into the body, although the higher probability of bleeding from the anus raises the risk a little bit for the giver and a hell of a lot for the receiver.

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Thanks for the thoughts. I realise these studies don't give the whole picture, but would be nice to see information.

To show how unreliable statistics are it should be remembered there are documented cases of one incidence of hetrosexual intercourse leading to a participant contracting the virus.

got linky?

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Thanks for the thoughts. I realise these studies don't give the whole picture, but would be nice to see information.

got linky?

I think you (as well as anybody else) will find quite difficult to find info about the quote above.

The closest I found, its vaguely mentioned in this article:

Aside from the obvious mistake of lumping together hepatitis B and HIV, there are no "alarming accounts [of infection] contracted after a single encounter"; quite to the contrary, so far there seems to be only one reported case in the United States of a person contracting HIV after a single exposure.

(I only asume it was a heterosexual encounter, if you read whole article, and the particular paragraph where it was written, but not sure and prepared to stand correctly)

Also: its mentioned one case in USA only, and not any mentioning if any other conditions or risks from either partners were existing.

Worth to read above article anyway. If you want to dig further, maybe you need to get the good old fashioned library, and find the works which mentioned there and research further. (as you not going to find everything on the net, according to the popular "belief")

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Sorry: forgot to mentioned that it was written over 23 years ago. (5-6 years after virus was found).

Judge for yourself, as somebody said: "we dread every attack, not for yourself, but for the books" :)

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Thanks for the link, I might well dig further.

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Most STD physicians have a degree of scepticism about what their patients tell them and, if you watched a programme (? Panorama) on BBC1 a couple of weeks ago which looked at the workings of the clinic at the Chelsea and Wesrminster Hospital, it's easy to see why. Many appeared unable to recall when they'd last had sex, who with and whether they'd used a condom.

So, suppose you have a study sample of 100 HIV +ve cases, 60 of whom say they are gay and 20 of whom say they are iv drug abusers and 20 deny both, then what do you make of this last 20? Are they all telling the truth or not? Some probably are and some probably aren't but, either way, this illustrates the difficulty of getting good statistics in the field

That said, there are many well-documented cases of heterosexual transmission, most obviously amonng the faithful partners of the infected.

As for risk calculations, I can't get you free full text version, only an abstract, but see:

.

Lancet Infect Dis. 2008 Sep;8(9):553-63. Epub 2008 Aug 4.

Rethinking the heterosexual infectivity of HIV-1: a systematic review and meta-analysis.

Powers KA, Poole C, Pettifor AE, Cohen MS.

Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599-7435, USA. powersk@email.unc.edu

Abstract

Studies of cumulative HIV incidence suggest that cofactors such as genital ulcer disease, HIV disease stage, and male circumcision influence HIV transmission; however, the heterosexual infectivity of HIV-1 is commonly cited as a fixed value (approximately 0.001, or one transmission per 1000 contacts). We sought to estimate transmission cofactor effects on the heterosexual infectivity of HIV-1 and to quantify the extent to which study methods have affected infectivity estimates. We undertook a systematic search (up to April 27, 2008) of PubMed, Web of Science, and relevant bibliographies to identify articles estimating the heterosexual infectivity of HIV-1. We used meta-regression and stratified random-effects meta-analysis to assess differences in infectivity associated with cofactors and study methods. Infectivity estimates were very heterogeneous, ranging from zero transmissions after more than 100 penile-vaginal contacts in some serodiscordant couples to one transmission for every 3.1 episodes of heterosexual anal intercourse. Estimates were only weakly associated with study methods. Infectivity differences, expressed as number of transmissions per 1000 contacts, were 8.1 (95 % CI 0.4-15.8) when comparing uncircumcised to circumcised susceptible men, 6.0 (3.3-8.8) comparing susceptible individuals with and without genital ulcer disease, 1.9 (0.9-2.8) comparing late-stage to mid-stage index cases, and 2.5 (0.2-4.9) comparing early-stage to mid-stage index cases. A single value for the heterosexual infectivity of HIV-1 fails to reflect the variation associated with important cofactors. The commonly cited value of 0.001 was estimated among stable couples with low prevalences of high-risk cofactors, and represents a lower bound. Cofactor effects are important to include in epidemic models, policy considerations, and prevention messages

Also do understand what a 1/1000 (0.001)risk is--- it is a per exposed risk. It means that, after the first expose there is a 0.999 (=99.9%) probability that you remain uninfected. After 2 exposures it is 0.999 x 0.999, after 3, 0.999 x 0.999 x 0.999 and so on. Gradually and inexorably, with an HIV positive regular partner the probability moves to odds-on.

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Thanks for the link. The discordant couples studies it references are worth checking out if you're interested.

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