It is time for another entry into the mailbag series where I answer feedback email from readers and others. If you want to send me a question, comment or any other kind of feedback, please do so using the contact form on the about page.
This time, the reader feedback comes from Paul and the topic is HIV/AIDS denialism.
For those new to this topic, HIV/AIDS denialism is a loosely organized movement of people who oppose mainstream medicine on the topic of HIV/AIDS. Depending on the specific subgroups, common beliefs are:
(1) that HIV does not exist despite the fact that many HIV strains has been isolated and sequences, that scientists have taken scanning electron micrographs of budding HIV and even three dimensional cryo-electron microscopy and tomography of the overall morphology, core, migration and budding sites of native HIV-1 virus particles (NIAID, 2010; HIV Sequence Database, 2010; Public Health Image Library, 2005; Carlson et al, 2010, de Marco et al, 2010, Zhao et al, 2013; Earl et al, 2013).
(2) that HIV does not cause AIDS despite the fact that HIV fulfills Koch’s postulates, is the single strong predictor of AIDS over different populations, that highly specific antiviral therapies against HIV drastically reduces the likelihood of developing AIDS and dying, HIV impairs and destroys CD4+ T cells in vivo and in vitro, leading to severe immune suppression and so on. Together with many other independent lines of evidence (NIAID, 2010), the conclusion that HIV causes AIDS is among the most evidence-based causal links between any pathogen and disease syndrome.
(3) that antiretroviral medication is the cause of HIV, despite the fact that many clinical trails have found huge improvements in delaying the onset of AIDS (two-drug combinations increased it by 50%, three-drug combinations increased it an additional 50-80%) and despite the sad fact that most people with HIV, especially in poorer countries in e. g. Africa, has never gotten antiretroviral medication and despite the fact that antiretrovirals (NIAID, 2010).
With that background information, let us turn to Paul and his comments. He sent me two feedback messages. The first is the standard tone troll accusation:
I respect how you are addressing these issues. If you have strong scientific evidence for your positions, then it is not necessary to use degrading terms to describe those holding opposing views. Simply put forth your arguments. They will be much more effective that way.
In other words, Paul does not bother dispute any of the arguments I make against HIV/AIDS denialism in this first message (although he will do this in his second message). Instead, he complains about tone. In the second feedback message, he quotes from the blog post where I debunk the flawed paper written by Duesberg, Bauer and others that was published in the obscure 0.5 impact factor journal called Italian Journal of Anatomy and Embryology. Paul claims that I describe HIV/AIDS denialists using “degrading term”. In reality, the only debatable case of “degrading terms” in that post about the flawed Duesberg paper is calling Henry Bauer homophobic. This is because he claimed in his 1988 book “To Rise Above Principle: The Memoirs of an Unreconstructed Dean” that homosexuality was an abbreviation or illness. He has since altered his views on homosexuality somewhat, which I noted in my later post about Henry Bauer’s central falsehoods about HIV/AIDS. With the tone trolling out of the way, let us examine Paul’s second feedback message.
He starts by quoting a paragraph from my refutation of the Duesberg paper. The paragraph was about Duesberg’s flawed comparison between the spread of plague and HIV.
Duesberg et. al. (2011) tries to compare the spread of infectious diseases such as plague caused by Y. pestis with HIV and concludes that since the spread of HIV and incidence of AIDS does not match that of the typical infectious diseases, this means that HIV cannot be the cause of AIDS or of an infectious epidemic. This is a flawed analogy, because unlike plague, HIV does not spread through casual, non-sexual contact as Y. pestis can and HIV/AIDS can take several years to be clinically obvious, rather than having an incubation time of a couple of days (Hoofnagle, 2011).
Paul does not bother to provide any counterarguments to this refutation. Instead, he trots out a couple of common denialist talking-points: that HIV allegedly cannot be transmitted sexually and that the long clinical latency of HIV (which he incorrectly calls incubation period) is just something that Robert Gallo supposedly had to make up to explain why “folks with HIV” (presumably Paul is referring to long-term nonprogressors) did not get AIDS.
You state this as a matter of obvious fact without addressing the fundamental issue of HIV as cause of AIDS without which sexual transmission is proven false. In addition no other virus has a 10 year incubation period. Please address this. On the face of it, it seems as though Gallo had to come up with some reason why folks who had HIV weren’t coming down with AIDS, well let’s call it a 10 yr incubation period. Where are the studies to show that all or at least high percentages of people who have HIV will necessarily have AIDS after 10 years?
HIV is transmitted sexually
The first sentence talking about sexual transmission is a little bit unclear. Presumably, “without which sexual transmission is proven false” refers to the HIV/AIDS denialist claim that HIV allegedly cannot be transmitted sexually. However, this belief is based on flawed, unscientific arguments and quotes taken out of context from published papers.
Perhaps the most well-known quote-mine is from a paper by Padian (1997). The study looked at heterosexual, serodisconcordant couples (where one partner has HIV and the other does not) and how behavioral interventions such as condoms and other safe-sex practices could reduce the spread of HIV to the uninfected partner. The sentence taken out of context is “Infectivity for HIV through heterosexual transmission is low”, was a conclusion drawn from the fact that condoms and other safe-sex practices prevented the spread of HIV, not that HIV cannot be transmitted sexually. Nancy Padian, Professor of Obstetrics, Gynecology and Reproductive Sciences at the University of California and the lead author of the paper, has written a response to the HIV/AIDS denialists who misuse her paper (AIDSTruth, 2010):
HIV is unquestionably transmitted through heterosexual intercourse. Indeed, heterosexual intercourse is now responsible for 70-80% of all HIV transmissions worldwide (2). The current likelihood of male to female infection after a single exposure to HIV is 0.01-0.32% (2, 3), and the current likelihood of female to male infection after a single exposure is 0.01-0.1% (2). These estimates are mostly derived from studies in the developed world. However, a man or a woman can become HIV-positive after just one sexual contact. In developing countries, particularly those in sub-Saharan Africa, several factors (co-infection with other sexually transmitted diseases, circumcision practices, poor acceptance of condoms, patterns of sexual partner selection, locally circulating viral subtypes, high viral loads among those who are infected, etc.) can increase the likelihood of heterosexual transmission to 20% or even higher (4). Evidence that specifically documents the heterosexual transmission of HIV comes from studies of HIV-discordant couples (i.e., couples in a stable, monogamous relationship where one partner is infected and the other is not); over time, HIV transmission occurs (5). Other studies have traced the transmission of HIV through networks of sexual partners (6-9). Additional evidence comes from intervention studies that, for example, promote condom use or encourage reductions in the numbers of sexual partners: the documented success of these interventions is because they prevent the sexual transmission of HIV (1,10,11).
In short, the evidence for the sexual transmission of HIV is well documented, conclusive, and based on the standard, uncontroversial methods and practices of medical science. Individuals who cite the 1997 Padian et al. publication (1) or data from other studies by our research group in an attempt to substantiate the myth that HIV is not transmitted sexually are ill informed, at best. Their misuse of these results is misleading, irresponsible, and potentially injurious to the public.
A common practice is to quote out of context a sentence from the Abstract of the 1997 paper: “Infectivity for HIV through heterosexual transmission is low”. Anyone who takes the trouble to read and understand the paper should appreciate that it reports on a study of behavioural interventions such as those mentioned above: Specifically, discordant couples were strongly counseled to use condoms and practice safe sex (1,12). That we witnessed no HIV transmissions after the intervention documents the success of the interventions in preventing the sexual transmission of HIV. The sentence in the Abstract reflects this success – nothing more, nothing less. Any attempt to refer to this or other of our publications and studies to bolster the fallacy that HIV is not transmitted heterosexually or homosexually is a gross misrepresentation of the facts and a travesty of the research that I have been involved in for more than a decade.
If safe sex practices are followed, and if there are no complicating factors such as those mentioned above, the risk of HIV transmission can be as low as our studies suggests. But many people misunderstand probability: they think that if the chance of misfortune is one in six, that they can take five chances without the likelihood of injury. This “Russian Roulette” misapprehension is dangerous to themselves and to others. Furthermore, complicating factors are often not evident or obvious in a relationship, so their perceived absence should not be counted on as an excuse not to practice safe sex.
The HIV/AIDS denialist Henry Bauer has put forward several flawed arguments against the sexual transmission of HIV. These can be refuted without much effort (Kalichman, 2009). Let us look at two specific examples:
Bauer compares HIV data from U.S. military recruits with reported cases of AIDS 10 years later. However, the sample of U.S military recruits are grossly non-representative of the U. S. population terms of HIV risk factors (military recruits are less likely to come from urban areas, the U. S. military excludes individuals most at risk).
Whereas Duesberg makes a flawed comparison between HIV and plague, Bauer makes a similarly flawed comparison between HIV and bacterial infections such as gonorrhea, apparently not noticing that HIV cannot be reliably cured and thus has different epidemiological properties than gonorrhea. If you look at a viral infection like HSV-2, the data shows that HSV-2 closely follows HIV infections.
Clinical latency and long-term nonprogressors
The incubation period is the time period between exposure to a pathogen and the development of signs and symptoms. Paul falsely claim that HIV has an incubation period of 10 years. In reality, the incubation period of HIV is usually a couple of weeks. At this point, called the acute retroviral syndrome, the vast majority of HIV infected individuals experience flu-like symptoms. After the acute infection, HIV goes into a clinical latency period. The HIV virus still replicates but is being kept in check by CD8+ killer T cells. One of the reasons that the immune system cannot clear the HIV infection is because some of the viruses hide dormant inside cells. This period varies, but is usually between a couple of years and a decade. As key components of the adaptive immune system becomes increasingly damaged by the infection, the progression towards AIDS occurs.
Robert Gallo did not invent the clinical latency period to “explain away” why people with HIV did not progress to AIDS. Without treatment, the vast majority of individuals infected with HIV will progress to AIDS. However, there are a very small proportion of individuals with HIV that will not progress to AIDS. These are called long-term nonprogressors. As I explained in a previous blog post:
Long-term nonprogressors are very few
—> Fewer than 1% of HIV-infected individuals are termed long-term nonprogressors. This means that they have viral particles in their blood, but do not develop AIDS. This does not qualify as “many” by any stretch of the imagination.
—> The exact genetic basis of this phenomena is largely unknown, but genome association studies suggests that the MHC locus may be involved. Specific HLA class I loci have also been linked to lack of disease progression (Abbas, 2012, pp. 467-468). This just means that HIV does not cause AIDS in these very few individuals. It does nothing against the well-supported evidence that HIV causes AIDS in the other ~99% of infected individuals. It is merely a feeble attempt by Bauer to deploy an argument from ignorance by focusing on what is unknown why ignoring the vast amount of accumulated knowledge.
Where are the studies!?
Paul asks “where are the studies to show that all or at least high percentages of people who have HIV will necessarily have AIDS after 10 years?”. Since we have access to highly effective antiretroivral medication, no ethical review board would approve such study and no ethical scientist with a shred of empathy would carry it out. This is because they would sentence a certain proportion of the study population to a drastic decline in health and a much shorter life-span. The fact that Paul does not seem to grasp such basic considerations in research ethics is telling.
However, studies have shown that individuals infected with HIV who respond to antiretroviral therapy have a much lower viral load and a much lesser risk of developing AIDS and dying than those that do not respond (NIAID, 2010).
Contrary to the beliefs of the HIV/AIDS denialist Paul, the sexual transmission of HIV is real and no amount of quote-mining or flawed comparisons between HIV and other infectious diseases is going to change that. Clinical latency is also an observed fact and nothing that Robert Gallo invented to explain away long-term nonprogressors. Finally, Paul does not seem to have any appreciation for basic research ethics when it comes to human subjects.
References and further reading
AIDSTruth. (2010). HIV heterosexual transmission and the “Padian paper myth”. Accessed: 2013-08-19.
Carlson, Lars-Anders, de Marco, Alex, Oberwinkler, Heike, Habermann, Anja, Briggs, John A. G., Kräusslich, Hans-Georg, & Grünewald, Kay. (2010). Cryo Electron Tomography of Native HIV-1 Budding Sites. PLoS Pathog, 6(11), e1001173.
de Marco, Alex, Müller, Barbara, Glass, Bärbel, Riches, James D., Kräusslich, Hans-Georg, & Briggs, John A. G. (2010). Structural Analysis of HIV-1 Maturation Using Cryo-Electron Tomography. PLoS Pathog, 6(11), e1001215. doi: 10.1371/journal.ppat.1001215
Earl, Lesley A., Lifson, Jeffrey D., & Subramaniam, Sriram. (2013). Catching HIV ‘in the act’ with 3D electron microscopy. Trends in Microbiology, 21(8), 397-404.
HIV Sequence Database. (2012). HIV Sequence Database FAQ. Accessed: 2013-08-19.
Kalichman, S. (2009). Denying AIDS: Conspiracy Theories, Pseudoscience and Human Tragedy. New York: Copernicus Books.
NIAID. (2010). The Evidence that HIV Causes AIDS. National Institutes of Allergy and Infectious Diseases. Accessed: 2013-08-03.
Public Health Image Library. (2005). Scanning electron micrograph of HIV-1 virions budding from a cultured lymphocyte.. Accessed: 2013-08-03.
Zhao, Gongpu, Perilla, Juan R., Yufenyuy, Ernest L., Meng, Xin, Chen, Bo, Ning, Jiying, . . . Zhang, Peijun. (2013). Mature HIV-1 capsid structure by cryo-electron microscopy and all-atom molecular dynamics. Nature, 497(7451), 643-646.