Aa
theoretical risks
Hello,
I have a general question. If a male gets infected via contact with a female HIV positive person, and that contact happens by (condom) protected intercourse and unprotected oral sex (on the woman), then how would that infection be classified in the records? Since both are very low risk activities, which activity will be assigned to be the culrpit? Will it be classified as having occurred due to sexual intercourse, even though it was protected? And if so, is it possible that the risk due to oral sex is being underestimated because it is the "classification of last resort", so to speak? Outside of teenagers, most people who engage in unprotected oral probably also have at least protected sexual intercourse (vaginal or anal), and isn't it possible that the transmission may actually have occurred orally, but is being counted as having occurred from protected sex?
Hope that convoluted paragraph makes sense....
I have a general question. If a male gets infected via contact with a female HIV positive person, and that contact happens by (condom) protected intercourse and unprotected oral sex (on the woman), then how would that infection be classified in the records? Since both are very low risk activities, which activity will be assigned to be the culrpit? Will it be classified as having occurred due to sexual intercourse, even though it was protected? And if so, is it possible that the risk due to oral sex is being underestimated because it is the "classification of last resort", so to speak? Outside of teenagers, most people who engage in unprotected oral probably also have at least protected sexual intercourse (vaginal or anal), and isn't it possible that the transmission may actually have occurred orally, but is being counted as having occurred from protected sex?
Hope that convoluted paragraph makes sense....
MEDICAL PROFESSIONAL
You are greatly underestimating the difficulties in conducting the kind of research you imply. It is true that general conclusions can be drawn from the sorts of sexually active persons and couples you describe, and such work is the basis of most current estimates of transmission efficiency in various settings. However, there just are not very many such persons (since most sexually transmitted HIV occurs in people with literally hundreds of potential exposures), or they are hard to find and identify, or they are not inclined to participate as research subjects. Further, few people have such consistent sexual practices, e.g. always condoms for vaginal, always unprotected oral, etc.
Therefore, the more precision you want in calculating transmission efficiency, the more necessary it is to know the details of exactly which sexual encounter was the one when the virus was transmitted. These are very difficult studies to do. As to how an exposure would be classified "for research purposes", this would depend on the details of study design and would not necessarily be the same in all such studies.
Finally, it is absolutely impossible to come up with accurate estimates for sexual practices that are inherently low risk. If the estimate is true that HIV is transmitted from an infected oral partner to the penile partner in oral sex one time in 20,000, then in order to accurately confirm that figure with strong statistical power, you would need at least a few hundred thousand such exposures, all of them known for sure to involve an infected oral partner and an uninfected partner who had no other possible exposures. Impossible. The same would be true of commercial vaginal sex transmissions. With only around 1 in 100 to 1 in 1000 commercial sex workers having HIV in most of the US and industrialized countries, and with condom use being the norm in commercial sex, it would take millions of exposures to accurate calculate the exate rate of HIV transmission "to johns from prostitutes".
We are almost 30 years into the known HIV/AIDS epidemic and the best we have are rough estimates of transmission risk. I'll bet that when we are 60 years into it -- i.e. around 2040 -- we will have no more precise data than we have now. That's just the way it is.
These are interesting issues, but that will have to end it. I won't have further comments. Stay safe!
Therefore, the more precision you want in calculating transmission efficiency, the more necessary it is to know the details of exactly which sexual encounter was the one when the virus was transmitted. These are very difficult studies to do. As to how an exposure would be classified "for research purposes", this would depend on the details of study design and would not necessarily be the same in all such studies.
Finally, it is absolutely impossible to come up with accurate estimates for sexual practices that are inherently low risk. If the estimate is true that HIV is transmitted from an infected oral partner to the penile partner in oral sex one time in 20,000, then in order to accurately confirm that figure with strong statistical power, you would need at least a few hundred thousand such exposures, all of them known for sure to involve an infected oral partner and an uninfected partner who had no other possible exposures. Impossible. The same would be true of commercial vaginal sex transmissions. With only around 1 in 100 to 1 in 1000 commercial sex workers having HIV in most of the US and industrialized countries, and with condom use being the norm in commercial sex, it would take millions of exposures to accurate calculate the exate rate of HIV transmission "to johns from prostitutes".
We are almost 30 years into the known HIV/AIDS epidemic and the best we have are rough estimates of transmission risk. I'll bet that when we are 60 years into it -- i.e. around 2040 -- we will have no more precise data than we have now. That's just the way it is.
These are interesting issues, but that will have to end it. I won't have further comments. Stay safe!
Thanks Doc, but I don't see why it has to be a single encounter. What about people who have multiple encounters of that sort: unprotected oral, protected anal/vaginal. There are many such categories: people in sero-discordant relationships, people who are promiscuous but careful, men who visit hookers on a regular basis, the hookers themselves who don't have boyfriends etc. If a transmission occured, and a person swore that since her/his last testing s/he had several encounters of only this form, then for research purposes, would the infection be presumed to have happened from oral or possible condom failure or "other"?
Incidentally, I notice that a lot of the questions here relate to hookers in particular - how common is transmission to johns from prostitutes?
Incidentally, I notice that a lot of the questions here relate to hookers in particular - how common is transmission to johns from prostitutes?
MEDICAL PROFESSIONAL
There is a typo in paragraph 5, where the correct statement is "...it would have to be known for sure the person was UNinfected before that exposure...."
MEDICAL PROFESSIONAL
Welcome to the forum. This is a fairly important question, since it gets to how people should interpret statistics about HIV transmission, including the transmission risks we cite on this forum.
First of all, no ongoing HIV/AIDS statistics classify people by the exact mechanism of infection. All the data are just classified as men having sex with men, hetersexually active men with no samesex partners, hetersexually active women with no same-sex partners, injection drug users, or combinations of these risk factors. There are no formal data related to whether the exposure was by anal sex, vaginal sex, oral sex, etc.
All the data on specific sexual practices come from a few research studies, in which the investigators asked more detailed questions than usually asked for routine case reporting. I can't say how such the researchers would classify a case like you describe. But this question is moot anyway; it would rarely if ever come up.
Why not? Because the large majority of HIV infected people do not know exactly when and how they were infected. Almost everybody with sexually acquired HIV has had multiple exposure. Most of those involved not only multiple exposures, but many different sex partners. They may make an educated guess about which partner and which specific exposure is responsible for their own infection, but usually they do not know and their guesses are just that, guesses. Finally, most new HIV diagnoses are made in people who in fact were infected for a few years before the positive blood test was done -- so all the data also are affected by the quality of someone's memory about distant past exposures.
To come across the dilemma you describe, it would have to be a person with HIV that was both newly acquired and newly diagnosed HIV, who had a single known exposure involving both condom protected vaginal sex plus unprotected cunnlingus, and it would have to be known for sure the person was infected before that exposure (i.e., having been tested with a negative result sometime in the recent past). Such a circumstance probably has never happened. It is true that many sexually active people have protected genital and unprotected oral sex. But almost none of them catch HIV, so really it's not a dilemma at all. A more likely scenario is UNprotected vaginal or anal sex, as well as unprotected oral.
A final comment comes back to our commonly cited figures for the risk of various sexual exposures. Those should be viewed only as very rough approximations -- because the data come from people making educated guesses, as discussed above. And they also are highly variable between partners and situations. For example, even though the average vaginal sex transmission risk is around 1 in 1,000, there are cases known where a single man infected 10 or more women, some of whom were only exposed once.
Regards-- HHH, MD
First of all, no ongoing HIV/AIDS statistics classify people by the exact mechanism of infection. All the data are just classified as men having sex with men, hetersexually active men with no samesex partners, hetersexually active women with no same-sex partners, injection drug users, or combinations of these risk factors. There are no formal data related to whether the exposure was by anal sex, vaginal sex, oral sex, etc.
All the data on specific sexual practices come from a few research studies, in which the investigators asked more detailed questions than usually asked for routine case reporting. I can't say how such the researchers would classify a case like you describe. But this question is moot anyway; it would rarely if ever come up.
Why not? Because the large majority of HIV infected people do not know exactly when and how they were infected. Almost everybody with sexually acquired HIV has had multiple exposure. Most of those involved not only multiple exposures, but many different sex partners. They may make an educated guess about which partner and which specific exposure is responsible for their own infection, but usually they do not know and their guesses are just that, guesses. Finally, most new HIV diagnoses are made in people who in fact were infected for a few years before the positive blood test was done -- so all the data also are affected by the quality of someone's memory about distant past exposures.
To come across the dilemma you describe, it would have to be a person with HIV that was both newly acquired and newly diagnosed HIV, who had a single known exposure involving both condom protected vaginal sex plus unprotected cunnlingus, and it would have to be known for sure the person was infected before that exposure (i.e., having been tested with a negative result sometime in the recent past). Such a circumstance probably has never happened. It is true that many sexually active people have protected genital and unprotected oral sex. But almost none of them catch HIV, so really it's not a dilemma at all. A more likely scenario is UNprotected vaginal or anal sex, as well as unprotected oral.
A final comment comes back to our commonly cited figures for the risk of various sexual exposures. Those should be viewed only as very rough approximations -- because the data come from people making educated guesses, as discussed above. And they also are highly variable between partners and situations. For example, even though the average vaginal sex transmission risk is around 1 in 1,000, there are cases known where a single man infected 10 or more women, some of whom were only exposed once.
Regards-- HHH, MD
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