Have you seen these two recentmeta-analysis of HIV transmission rates? Comparing them to your numbers, it seems that Wikipedia/CDC have greatly understated the risk for P/A sex acts (due to using older studies?).
Also, according to this page, the transmission rates for genital herpes are similar to HIV for P/V sex acts, so AIDS is not the only STD to have such low transmission rates.
it would still require an unrealistic initial foothold in the population by other means before it could ever spread sexually
I think the conventional theory is that HIV established an initial foothold by means such as needle sharing, blood transfusions, and P/A sex acts. That seems quite realistic to me. Why do you think it’s unrealistic?
No I haven’t seen them until now. I haven’t really been looking into or thinking about this until just recently.
I originally quoted the wikipedia data, which several us tracked down and analyzed in another thread (it comes from the CDC and originally from a single medium-ish European study which I think did a fairly good job to control for factors such as condom use and what not given the complexities):
It is claimed that HIV is a sexually transmitted disease. However, the typical estimates of transmission rate are extremely low: 0.05% / 0.1% per insertive/receptive P/V sex act 0.065% / 0.5% per insertive/receptive P/A sex act
Let’s compare to the 1st meta-analysis:
it finds 0.04/0.08% for insertive/receptive P/V sex in the 1st world, very similar but slightly lower to the older CDC study (from europe). They find the rates are around 5 times higher in the 3rd world.
For P/A receptive, they find a pooled per-act rate of 1.7%, about 3.5 times higher than the 1st world CDC study. I suspect this is simply because they pooled 1st and 3rd world data together.
This does not show that Wikipedia/CDC have “greatly understated” the risk for P/A sex acts—this data is in agreement. The variance is between 1st and 3rd world studies. The 1st world data is of paramount concern for the historical origin theory of the disease. The 3rd world data is a side point—not historically important and suspect in general, as in fact mentioned in the abstract.
The abstract:
We did a systematic review and meta-analysis of observational studies of the risk of HIV-1 transmission per heterosexual contact. 43 publications comprising 25 different study populations were identified. Pooled female-to-male (0·04% per act [95% CI 0·01—0·14]) and male-to-female (0·08% per act [95% CI 0·06—0·11]) transmission estimates in high-income countries indicated a low risk of infection in the absence of antiretrovirals. Low-income country female-to-male (0·38% per act [95% CI 0·13—1·10]) and male-to-female (0·30% per act [95% CI 0·14—0·63]) estimates in the absence of commercial sex exposure (CSE) were higher. In meta-regression analysis, the infectivity across estimates in the absence of CSE was significantly associated with sex, setting, the interaction between setting and sex, and antenatal HIV prevalence. The pooled receptive anal intercourse estimate was much higher (1·7% per act [95% CI 0·3—8·9]). Estimates for the early and late phases of HIV infection were 9·2 (95% CI 4·5—18·8) and 7·3 (95% CI 4·5—11·9) times larger, respectively, than for the asymptomatic phase. After adjusting for CSE, presence or history of genital ulcers in either couple member increased per-act infectivity 5·3 (95% CI 1·4—19·5) times versus no sexually transmitted infection. Study estimates among non-circumcised men were at least twice those among circumcised men. Low-income country estimates were more heterogeneous than high-income country estimates, which indicates poorer study quality, greater heterogeneity of risk factors, or under-reporting of high-risk behaviour. Efforts are needed to better understand these differences and to quantify infectivity in low-income countries.
So this supports the original CDC data for the 1st world.
The second meta-study finds a receptive A per act rate of 1.4%, a little lower than the 1st study, and about 2.8 times the 1st world CDC data. They make no mention of what countries, and I assume it mixes 3rd and 1st world data—it is a large meta-analysis of many studies.
There is also some serious wierdness in the 2nd study:
Per-partner combined URAI–UIAI summary estimates, which adjusted for additional exposures other than AI with a ‘main’ partner [7.9% (95% CI 1.2–14.5)], were lower than crude (unadjusted) estimates [48.1% (95% CI 35.3–60.8)].
Our modelling demonstrated that it would require unreasonably low numbers of AI HIV exposures per partnership to reconcile the summary per-act and per-partner estimates, suggesting considerable variability in AI infectiousness between and within partnerships over time.
So something doesn’t fit—the per act and per partner numbers don’t square up at all. Somewhere else someone posted an abstract with a similar result, how basically your chance of infection levels off quickly in couples and is much lower than you think—you are either going to get it or not irregardless of number of sex acts. This suggests that there are some major unknown immunity factors at work or the entire model is wrong.
I think the conventional theory is that HIV established an initial foothold by means such as needle sharing, blood transfusions, and P/A sex acts. That seems quite realistic to me. Why do you think it’s unrealistic?
I think the needle sharing and blood transfusions is far more credible, but the 0.5% ish per act of receptive A in the 1st world could possibly support a sexual vector in the gay bathouse scene, but it is debatable.
The conventional theory requires that HIV came over as a mutated form of harmless simian SIV and spread here, through a single source vector from what I recall. Blood donation might make more sense, but one would have to look at the epidemiological models for that.
Have you seen these two recent meta-analysis of HIV transmission rates? Comparing them to your numbers, it seems that Wikipedia/CDC have greatly understated the risk for P/A sex acts (due to using older studies?).
Also, according to this page, the transmission rates for genital herpes are similar to HIV for P/V sex acts, so AIDS is not the only STD to have such low transmission rates.
I think the conventional theory is that HIV established an initial foothold by means such as needle sharing, blood transfusions, and P/A sex acts. That seems quite realistic to me. Why do you think it’s unrealistic?
No I haven’t seen them until now. I haven’t really been looking into or thinking about this until just recently.
I originally quoted the wikipedia data, which several us tracked down and analyzed in another thread (it comes from the CDC and originally from a single medium-ish European study which I think did a fairly good job to control for factors such as condom use and what not given the complexities):
Let’s compare to the 1st meta-analysis:
it finds 0.04/0.08% for insertive/receptive P/V sex in the 1st world, very similar but slightly lower to the older CDC study (from europe). They find the rates are around 5 times higher in the 3rd world.
For P/A receptive, they find a pooled per-act rate of 1.7%, about 3.5 times higher than the 1st world CDC study. I suspect this is simply because they pooled 1st and 3rd world data together.
This does not show that Wikipedia/CDC have “greatly understated” the risk for P/A sex acts—this data is in agreement. The variance is between 1st and 3rd world studies. The 1st world data is of paramount concern for the historical origin theory of the disease. The 3rd world data is a side point—not historically important and suspect in general, as in fact mentioned in the abstract.
The abstract:
So this supports the original CDC data for the 1st world.
The second meta-study finds a receptive A per act rate of 1.4%, a little lower than the 1st study, and about 2.8 times the 1st world CDC data. They make no mention of what countries, and I assume it mixes 3rd and 1st world data—it is a large meta-analysis of many studies.
There is also some serious wierdness in the 2nd study:
So something doesn’t fit—the per act and per partner numbers don’t square up at all. Somewhere else someone posted an abstract with a similar result, how basically your chance of infection levels off quickly in couples and is much lower than you think—you are either going to get it or not irregardless of number of sex acts. This suggests that there are some major unknown immunity factors at work or the entire model is wrong.
I think the needle sharing and blood transfusions is far more credible, but the 0.5% ish per act of receptive A in the 1st world could possibly support a sexual vector in the gay bathouse scene, but it is debatable.
The conventional theory requires that HIV came over as a mutated form of harmless simian SIV and spread here, through a single source vector from what I recall. Blood donation might make more sense, but one would have to look at the epidemiological models for that.