The lottery (like roulette) is a situation where the odds are always the same and are well known. The situation with HIV is more like that with casino blackjack. In a single deck blackjack game played with casino rules the odds fluctuate wildly depending on what cards have been dealt. By counting cards and betting small when the odds are against you and betting large when the odds favor you it is possible to win at the game. See the book "Beat the Dealer" by Edward O. Thorp for details. (The book is still in print and available from Amazon much to my surprise.) Warning: it is a lot of work for a slow return and if the house realizes that you are counting cards they are likely to take exception to you playing in their casino.
The risk of catching HIV is actually the product of three different probabilities two of which vary wildly and the third of which is not well known.
We can write:
p := p1 * p2 * p3
where p is the probability that you will become infected with HIV from a single sexual act.
p1 is the probability that your partner is infected with HIV. In a given encounter this probability is either 0 or 1. However, if you don't know his or her HIV status you don't know which of those numbers is the right one to use. The study estimates that 1% of the general hetrosexual population is infected. Unfortunately, this tells you nothing about a given partner. It simply tells you that if you have sex with a large number of partners with unknown HIV status that 99% of the time p1 will be 0 and 1% of the time p1 will be 1. This is very different from p1 always being 0.01 in every encounter.
What we really need is a simple on-the-spot test for HIV infection -- something like: spit on this piece of paper and it turns red if you are infected. Being able to avoid sex with persons infected with HIV would give us 100% protection against the disease without using any protection at all.
p2 is the probability that your protection will fail and potentially expose you to the virus. If you aren't using protection p2 is 1. The authors of the study appear to assume that you both are completely safe if the condom does not fail. They assume that the failure rate with condoms is 5% and therefore use a constant value of 0.05 for p2 if you are using a condom. Actually, I suspect that the failure rate depends on many factors including the act being performed. I doubt that condoms fail very often in oral sex. I have no first hand experience with anal sex, but I have read that condoms are not designed for this usage and have a much higher than usual failure rate for this act. As I have stated in an earlier post, if a condom does not fail it should give the woman almost complete protection against being exposed to the man's semen. I am not convinced that a condom gives a man much protection against exposure to the woman's vaginal fluids especially if he engages in DATY. Fortunately, HIV is found primarily in the semen and the blood and only in very small amounts in other bodily fluids.
p3 is the probability that you will become HIV positive if you engage in a particular sex act with a partner who is HIV positive and you do not use protection. In spite of the estimates in the study I doubt that these numbers are very trustworthy.
We are all fortunate that HIV is difficult to transmit. I remember that in the early days of the AIDS that the number of cases was doubling every year. That was pretty horrifying, but stop for a moment and think what it means. Nobody knew what was causing the disease so nobody was taking any precautions. The disease at that time was primarily in the gay population. These guys were having a lot of sex and a lot of that sex was anal. In spite of that the rate at which the disease was spreading means that on average each infected person was only managing to infect one new person PER YEAR. The odds against passing the virus in any single sex act must be quite small. However, remember that events with small probabilities do happen -- they just don't happen very often. People do win the lottery (and do get struck by lighting).
Nevada requires women working in the legal bordellos in Nevada to be tested on a regular basis for HIV. To the best of my knowledge some women applying to work in a legal bordello have been turned down because they were HIV positive but no woman working in a legal bordello in Nevada has EVER become HIV positive while working there. (However, I have heard rumours that there have been a few such cases and they were covered up. I doubt that the rumors are true, but I could be wrong.) If somebody knows what the truth is here and can post a link I would be grateful.
We should be very thankful that this disease does not spread like the flu. According to Scientific American only about 1% of the population (due to a recessive gene inherited from both parents) lacks the receptors that the virus uses to gain entry to cells and therefore is immune to the disease. Society would collapse with far less than a 99% loss of the population.
http://dailynews.yahoo.com/h/hsn/20020116/hl/study_predicts_aids_risk_from_different_sex_acts_1.html
It took me some time to cross reference the statements in the article and figure out the actual risks for various acts. Having done the work I thought others might like to see the results.
The following assumes, of course, that the study has calculated risks correctly and the article is accurately quoting them.
First, we need a benchmark. Numbers in isolation don't mean much. If you are in the 25-44 age group your chances of falling and dying in your home this year are 1 in 250,000. That is 160 in 40,000,000. Remember the number 160 for comparison because I am going to normalize all risks to chances in 40,000,000.
The following are the risks for men and women IN A SINGLE ACT in which HIV status of both partners is unknown and the man is NOT BISEXUAL.
Man:
BB DATY = 40 (out of 40,000,000)
BB BJ = 20
BB FS = 200
BB Anal = 260
C DATY = 2
C BJ = 1
C FS = 10
C Anal = 13
Woman:
BB DATY = 20
BB BJ = 40
BB FS = 400
BB Anal = 2,000
C DATY = 1
C BJ = 2
C FS = 20
C Anal = 100
Thus, if the authors are correct a woman giving a BBBJ to a straight male with unknown HIV status has about 1/4 the risk of becoming HIV positive from that single act as she has of falling and dying in her home this year if she is in the 25 to 44 age range.
As always, repetition is important. If the woman gives 1000 BBBJ's this year to straight partners with unknown HIV status her risk of becoming HIV positive goes up from 1 in a million to about 1 in a thousand.
If the authors are correct a woman's risk in allowing BB DATY is about the same as C FS. The man's risk with BB FS is about 5 times his risk with BB DATY.
Interesting numbers, but remember the authors say that there is a large uncertainty attached to the calculation of these numbers.
The author's estimate of risk seems to be linear with their estimate of the fraction of the population carrying the HIV virus. This seems to me to be a good estimate of overall risk but isn't much use in a given situation. Your risk of becoming HIV positive is exactly zero if your partner isn't HIV positive. If your partner is HIV positive your risk is about 100 times the numbers given since the authors assume that 1% of the straight population is HIV positive. Monogamy with a HIV negative partner is the safest sex. Monogamy with a HIV positive partner is the most dangerous sex -- much more dangerous than promiscuity.
The author's estimate that covered sex is 20 times safer than uncovered sex seems to be directly related to their estimate of a 5% breakage rate for condoms. This seems to me to be accurate for women. If she isn't exposed to your semen she is probably almost completely safe. It doesn't seem to me to be true for men. If you DATY (without a shield -- and nobody I know uses a shield) you are almost as exposed to her vaginal fluids as you would be in BBFS -- not quite, but almost.
-- Modified on 1/17/2002 9:33:35 PM
-- Modified on 1/17/2002 10:31:56 PM
Of course, that's what the numbers say is the safest acts.
I assume, they don't consider the mental stress that would result.
As John F. Ross says in the book "The Polar Bear Strategy: Reflections on Risk in Modern Life" (published by Perseus Books), "One person's high risk is another's lark. Anyone who's ever managed people, maintained friendships, or kept a marriage healthy has a good working knowledge of this basic tenet. It's a fact of life. Some people seek great physical risks as war correspondents or professional mountain climbers. Others avoid them at all costs. Some academics seek high intellectual risks, others shun them. Until recently, psychologists believed that much of these personal differences among people were rooted in socialized or learned behavior. New research suggests that some of our predisposition or antagonism toward risk is rooted in biological functions. In other words, part of the reason a person is risk averse or risk prone may be hard-wired, that is, built directly into the individual's physical makeup."
In general, I think that the numbers tell us what we already knew. Namely, that with something as deadly as HIV we don't want to be exposed to the blood or semen of a person who is a carrier for the virus.
A straight male is not going to be exposed to another male's semen and by avoiding certain times of the month can avoid being exposed to any significant amount of blood. (Remember that, as with any virus, load factor is important. If you get a blood transfusion with HIV positive blood you are almost certain to become HIV positive. If you are bitten by a mosquito which has just bitten a HIV positive person you are not going to become HIV positive. The amount of virus that is transferred is simply not enough to overcome your body's defenses.) In short, for the male -- unless he is extremely risk aversive -- condoms are not very significant when it comes to being safe from HIV (there are other STDs where they are a significant protection, of course -- and there are also STDs where they aren't).
For the woman I think condoms are very signficant. If they don't break they prevent exposure to the man's semen and give her almost complete protection against HIV (as well as many other STDs, not to mention pregnancy). Also, repetition increases risk and escorts have sex with clients far more often than most clients have sex with escorts. (Given the average spent by clients according to surveys on TER and given the average income of the top escorts I estimate that the client population is about 20 times as large as the escort population.)
-- Modified on 1/17/2002 11:05:56 PM
-- Modified on 1/18/2002 12:28:47 AM
about one in 30,000,000 ( Pardon me, Mathesar if I do not match your precision with numbers.) That translates to about:
1.3 in 40,000,000- higher than the odds of catching anything.
I guess the moral here is: If you should win the lottery and are planning to spend your winnings on a new provider every night for the rest of your life, you had better think twice.
Since you have beaten the odds with good luck, the scales of karma might just even out and sting you with the bad. LOL
The lottery (like roulette) is a situation where the odds are always the same and are well known. The situation with HIV is more like that with casino blackjack. In a single deck blackjack game played with casino rules the odds fluctuate wildly depending on what cards have been dealt. By counting cards and betting small when the odds are against you and betting large when the odds favor you it is possible to win at the game. See the book "Beat the Dealer" by Edward O. Thorp for details. (The book is still in print and available from Amazon much to my surprise.) Warning: it is a lot of work for a slow return and if the house realizes that you are counting cards they are likely to take exception to you playing in their casino.
The risk of catching HIV is actually the product of three different probabilities two of which vary wildly and the third of which is not well known.
We can write:
p := p1 * p2 * p3
where p is the probability that you will become infected with HIV from a single sexual act.
p1 is the probability that your partner is infected with HIV. In a given encounter this probability is either 0 or 1. However, if you don't know his or her HIV status you don't know which of those numbers is the right one to use. The study estimates that 1% of the general hetrosexual population is infected. Unfortunately, this tells you nothing about a given partner. It simply tells you that if you have sex with a large number of partners with unknown HIV status that 99% of the time p1 will be 0 and 1% of the time p1 will be 1. This is very different from p1 always being 0.01 in every encounter.
What we really need is a simple on-the-spot test for HIV infection -- something like: spit on this piece of paper and it turns red if you are infected. Being able to avoid sex with persons infected with HIV would give us 100% protection against the disease without using any protection at all.
p2 is the probability that your protection will fail and potentially expose you to the virus. If you aren't using protection p2 is 1. The authors of the study appear to assume that you both are completely safe if the condom does not fail. They assume that the failure rate with condoms is 5% and therefore use a constant value of 0.05 for p2 if you are using a condom. Actually, I suspect that the failure rate depends on many factors including the act being performed. I doubt that condoms fail very often in oral sex. I have no first hand experience with anal sex, but I have read that condoms are not designed for this usage and have a much higher than usual failure rate for this act. As I have stated in an earlier post, if a condom does not fail it should give the woman almost complete protection against being exposed to the man's semen. I am not convinced that a condom gives a man much protection against exposure to the woman's vaginal fluids especially if he engages in DATY. Fortunately, HIV is found primarily in the semen and the blood and only in very small amounts in other bodily fluids.
p3 is the probability that you will become HIV positive if you engage in a particular sex act with a partner who is HIV positive and you do not use protection. In spite of the estimates in the study I doubt that these numbers are very trustworthy.
We are all fortunate that HIV is difficult to transmit. I remember that in the early days of the AIDS that the number of cases was doubling every year. That was pretty horrifying, but stop for a moment and think what it means. Nobody knew what was causing the disease so nobody was taking any precautions. The disease at that time was primarily in the gay population. These guys were having a lot of sex and a lot of that sex was anal. In spite of that the rate at which the disease was spreading means that on average each infected person was only managing to infect one new person PER YEAR. The odds against passing the virus in any single sex act must be quite small. However, remember that events with small probabilities do happen -- they just don't happen very often. People do win the lottery (and do get struck by lighting).
Nevada requires women working in the legal bordellos in Nevada to be tested on a regular basis for HIV. To the best of my knowledge some women applying to work in a legal bordello have been turned down because they were HIV positive but no woman working in a legal bordello in Nevada has EVER become HIV positive while working there. (However, I have heard rumours that there have been a few such cases and they were covered up. I doubt that the rumors are true, but I could be wrong.) If somebody knows what the truth is here and can post a link I would be grateful.
We should be very thankful that this disease does not spread like the flu. According to Scientific American only about 1% of the population (due to a recessive gene inherited from both parents) lacks the receptors that the virus uses to gain entry to cells and therefore is immune to the disease. Society would collapse with far less than a 99% loss of the population.