Perplexed comments on Open Thread, September, 2010-- part 2 - Less Wrong

3 Post author: NancyLebovitz 17 September 2010 01:44AM

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Comment author: jacob_cannell 21 September 2010 01:32:49AM *  2 points [-]

Please see my response below concerning the perjorative "Denialist", and why such perjoratives have no place here.

If you want to get into a discussion about rationality and reasoning in highly politicized issues such as this, that is an interesting side topic.

No, I don't believe I do. I wouldn't want to further offend you.

You haven't offended me.

When I Googled, the first few hits I found suggested 0.3% per coital act as a lower bound on heterosexual transmissibility with the risks increasing by 1-2 orders of magnitude in case of genital ulcers and/or high viral loads

The google hits you mention are just websites, not research papers - not relevant. There is no reason apriori to view the ~0.3% per coital act transmission rate as a lower bound, it could just as easily be an upper bound. You need to show considerably more evidence for that point.

The data on wikipedia comes from the official data from the CDC1, which in turn comes from a compilation of numerous studies. I take that to be the 'best' data from the majoritive position, and overrides any other lesser studies for a variety of reasons.

It was pretty clear to me that the kinds of low numbers you were using to argue against HIV being an STD are actually based on monogamous couples who are regularly examined by physicians and have been instructed in the use of condoms to prevent transmission. Those numbers don't apply to the most common cases of transmission, in which ulcers and other factors make transmission much more likely.

This may be 'clear to you', but the Wikipedia data comes from a large CDC sponsored review considering aggregates of other studies to get overall measures of transmission. This is the orthodox data! I highly doubt it has the simple methodological errors you claim. And even if you did prove that it does have those errors, then you are only helping the skeptic case - by showing methodological errors in the orthodox position, and the next set of data should then come from the heterodox camp.

Comment author: Perplexed 21 September 2010 02:17:21AM 4 points [-]

I highly doubt it has the simple methodological errors you claim.

Well the best cure for doubt is to actually read the papers referenced. For example, following the links from your reference to the abstract of the actual paper which generated the numbers brought me to this abstract. I think you should read it.

The issue isn't methodological errors in the studies - the studies clearly describe the methodologies used and their limits. The issue is trying to use the numbers in ways that they are not designed to be used. It is not the orthodox folks that are doing that. It is you that is doing that.

Comment author: jacob_cannell 21 September 2010 02:31:46AM *  0 points [-]

The issue is trying to use the numbers in ways that they are not designed to be used. It is not the orthodox folks that are doing that.

Ah, so do the numbers come with little instruction manuals that say "CAN ONLY BE USED TO SUPPORT ORTHODOX POSITION"? Haha sorry, couldn't resist.

OK, I'm game, I will now look into the CDC studies, but let's be clear on the trace ..

it starts with the wikipedia chart which has the ref note 80 linked here, which points to this, which in turn lists refs 76, 77, and 79 for P/V sex, which are (in order):

76: Comparison of female to male and male to female transmission of HIV in 563 stable couples

77: Reducing the risk of sexual HIV transmission: quantifying the per-act risk for HIV on the basis of choice of partner, sex act, and condom use

79: European Study Group on Heterosexual Transmission of HIV. Heterosexual transmission of HIV: variability of infectivity throughout the course of infection

I'll comment more after I have read these.

Comment author: Perplexed 21 September 2010 03:04:52AM *  2 points [-]

You will find that #77, the Varghese et al paper, can be found online by Googling the title, and that it gets its 0.1% number for heterosexual transmission from the paper whose abstract I recommended.

I'm pretty sure you will find that all of these papers involve monogamous couples. If you give it some thought, you will realize that there is just about no other way to come up with a solid empirically-based number. And I again urge you to read that abstract - particularly the bottom third.

Comment author: jacob_cannell 21 September 2010 03:36:05AM *  0 points [-]

Haha ok this is kinda funny, but the abstract you linked to which is the source of the data in Varghese(77), is just 76! - the couple comparison from the European Study Group which I linked to and have been trying to parse. 79 appears to be another chapter from that same book, but I haven't looked at it yet.

So before we get into 76 - the source of the stat you don't like in 77, I need to backup and remember your original claim about the data:

It was pretty clear to me that the kinds of low numbers you were using to argue against HIV being an STD are actually based on monogamous couples who are regularly examined by physicians and have been instructed in the use of condoms to prevent transmission. Those numbers don't apply to the most common cases of transmission, in which ulcers and other factors make transmission much more likely.

Your implied point appears to be that couples in this study use condoms frequently. Surprisingly, this is not the case - only a surprisingly small number of couples reported consistent condom use (out of 500+),

Contraceptive behaviour:

No regular contraceptive 12 (10/86) 20 (43/212) Oral contraceptive 18 (7/40) 23 (26/114) Intrauterine device 10 (1/10) 28 (7/25) Condom* 0(0/11) 18 (6/33)

These people were using other methods of birth control more than condoms.

None of the 24 partners who had used condoms systematically since the first sexual contact was infected.

and they further removed consistent condom users from the data:

Assuming that no risk factors for transmission would be relevant during consistent condom use, eight male and 16 female contacts who were still negative and had systematically used condoms since the first sexual contact with the index case were excluded from the analysis of risk factors.

Comment author: Perplexed 21 September 2010 04:14:40AM 0 points [-]

Haha ok this is kinda funny, but the abstract you linked to which is the source of the data in Varghese(77), is just 76! - the couple comparison from the European Study Group.

No, it is not. The reference leading to the abstract is the absolute risk described in the first paragraph of page 40 of Varghese. It is reference 28 of Varghese.

You are apparently following the references (21) appearing in Table 1 of Varghese. But these are relative risks (relative to felatio). Not at all what I meant.

My point about condom use came from an earlier reference that I had supplied which discusses a study that took place in Uganda in 2005. And I didn't say that they used condoms frequently, I said that they were monogamous couples who got regular medical inspections and had been counseled regarding condoms. And in this study, as I recall, there was no exclusion of condom users.

Comment author: jacob_cannell 21 September 2010 04:33:50AM 0 points [-]

Ah no I haven't even read Varghese(77) yet. You looked at that one and posted a link to an abstract - this abstract, which comes from the same European Study Group and has the same numbers (563 couples) as 76. So the abstract you wanted me to look at is just 76, it's all the same source.

Satt also pointed this out in another reply here.

I'm not really concerned (at the moment) with what may or may not be happening in Uganda. The CDC data comes from this European Study Group, that is the original data in question - (the data you questioned).

Comment author: Jonathan_Graehl 21 September 2010 08:07:46PM 0 points [-]

in this study, as I recall, there was no exclusion of condom users.

I'm confused - the table says "assuming no condom use". So you're talking about other data, or they were able to filter the data.

Comment author: Perplexed 21 September 2010 09:01:20PM 0 points [-]

I'm confused - the table says "assuming no condom use".

What table in what document says that?

So you're talking about other data

I'm talking about the data I said I am talking about: this paper and this piece of primary research which states

Trial participants were enrolled as individuals; provided written, informed consent; and were guaranteed confidentiality. Condoms and voluntary HIV counseling and testing, for individuals and for couples, were promoted and provided free of charge. ... Antiretroviral therapy (ART) was not available in Uganda at the time of the study, but participants were offered free general health care and treatment for opportunistic infections.

Comment author: Jonathan_Graehl 21 September 2010 09:24:39PM 0 points [-]

The original table in the top-level comment. I guess you're off on a tangent then.

Comment author: Perplexed 21 September 2010 09:33:16PM -1 points [-]

I repeat. What table in what top-level comment? WTF is a "top-level comment?"

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