Here's a list of things about HIV/AIDS that intrigued or surprised me when I first learned of them. I have to admit: in more than one case I refused to believe the claim until I had what I thought was enough evidence to persuade me to believe it. (One generally shouldn't believe a counter-intuitive claim because a good friend of yours said she read it somewhere on the Internet.) So when writing this, I did my best to support each of the nine points with (what I hope is) sufficient reasoning.
I'm sure that when many people see some of these things they'll ask why
on earth I chose to put this list together. Wouldn't people be better off not knowing some of these things? Don't some of my statements trivialise the suffering of the hundreds of thousands of people infected with HIV across the region? Don't they undermine the efforts of our public-health sectors and non-governmental organisations? Isn't this just
foolish?
Maybe. I sincerely hope not and I honestly don't think so, but maybe.
The thing is, though, none of this is conspiratorial. This isn't anything like
evidence that HIV was brewed in a lab. This is stuff from free, public UN, WHO and governmental reports. This is Wikipedia and news stuff. This is Google stuff. This is stuff that's out there in plain sight for anyone who really bothers to look.
1. The risk of transmission of HIV/AIDS is much smaller than you probably think.What do you think is the chance of you contracting HIV from an unprotected sexual encounter with an HIV-positive person of the other sex? Over 50? Near certain? 110%?
The actual figure is closer to 0.1%.
A person's risk of contracting HIV in an unprotected sexual act depends on the type of sexual act and his/her role in the act. A study published in February reviewed other studies on the per-act risk of contracting HIV in unprotected sex[1]. It reported that studies done in developed countries found that the risk of female-to-male transmission is around 0.04% and the risk of male-to-female transmission is around 0.08%, while studies done in developing countries found a female-to-male transmission risk of 0.38% and a male-to-female risk of 0.30%. (The authors suspect that the difference is due to poorer study quality, greater heterogeneity of risk factors, and under-reporting of high-risk behaviour in low-income countries.) The Joint United Nations Programme on HIV/AIDS (UNAIDS) 2008 report on the global AIDS epidemic cites a study of Ugandan couples which found that the chances of an HIV-negative partner contracting HIV from his/her HIV-positive partner of the opposite sex is about 8%...per year [2]. The study itself nicely provides an average per-act risk of 0.12% with a peak of 0.82% immediately after HIV acquisition and a low of 0.07% between initial acquisition and the late stages of AIDS just before death [3].
These figures are for penile-vaginal sex. What about other types of sex? Oral intercourse is the least risky; there is about a 0.0005% risk for the insertive partner and 0.001% risk for the receptive partner. On the other hand, anal intercourse is the riskiest type of intercourse. Estimates put the risk for the receptive partner at between 0.5% [4] and 1.7% [1], and the risk for the insertive partner at 0.1% [4]. That's between 5 and 21 times riskier than vaginal sex for the receptive partner.
For comparison, the studies cited by the Wikipedia article on HIV list the risks of the non-sexual modes of transportation as follows: Blood transfusion, 90%; Mother to child, 25%; Needle sharing drug use, 0.67%; Percutaneous needle stick, 0.3% [4].
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1.
Boily M-C, Baggaley RF, Wang L, et al. (2009). "Heterosexual risk of HIV-1 infection per sexual act: systematic review and meta-analysis of observational studies". Lancet Infect Dis 9 (2): 118-129. PMID 19179227.
2. UNAIDS (2008). Report on the global AIDS epidemic. UNAIDS, Geneva. p. 43
3. Wawer MJ et al. (2005). Rates of HIV-1 transmission per coital act by stage of HIV-1 infection, in Rakai, Uganda. Journal of Infectious Diseases, 191:1403–1409.
http://www.who.int/hiv/events/artprevention/wawer.pdf4.
Wikipedia article on HIV -- Transmission. Check the table to the right and the studies they cite.
2. Perhaps HIV doesn't discriminate, but it certainly doesn't affect all groups of people equally.Certain groups are disproportionately[1] affected by HIV. These include prostitutes (or
commercial sex workers as they say in HIV/AIDS-speak), injecting drug users and gay men. Knowing what is commonly taught about HIV/AIDS, it isn't hard to figure out why prostitutes and injecting drug users would be disproportionately affected by HIV. It's perhaps less obvious why gay men -- or, as they say in the HIV/AIDS epidemiological community,
men who have sex with men (MSMs) -- are disproportionately affected. As a matter of fact, they were the first group known to be affected by the virus.
The virus that would later be termed HIV and the disease that would later be called AIDS were first discovered among gay men in the United States[2]. In some countries, men who have sex with men make up the majority of the male HIV/AIDS cases (despite being estimated to comprise between 5% and 7% of the male population)[3], and in many countries any man who admits ever having had sex with another man on his blood donor form is permanently barred from donating blood[4]. Men who have sex with men are also disproportionately affected in the Caribbean and experts believe that we underestimate how much of our epidemic is a result of sex between men, but they do not believe that our epidemic is significantly driven by sex between men [5]. In all but two countries, the AIDS epidemic is thought to be driven by heterosexual intercourse with roughly equal proportions of men and women having HIV and AIDS. The two exceptions are Dominica and Cuba. In both of those countries the majority of infected persons are men and sex between men is thought to be the main mode of transmission [6].
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1. A group X is disproportionately affected by HIV if the proportion of Xs in a population differs significantly from the proportion of Xs with HIV in that same population. For example, Xs are disproportionately affected by HIV if they make up 2-5% of the general population but 20-25% of the HIV-positive population.
2. This is fairly well known but many people may not have heard it since there's little reason for the Caribbean's HIV/AIDS campaigns to mention it. Evidence:
This BBC article,
this link on the US Centers for Disease Control website, and
this random blog entry.
3. The USA, Canada and Australia are three such countries. Check
here for the US,
here for Canada and
here for Australia. The 5% to 7% figure is in the link for the US.
4. See National Health Service of the United Kingdom,
Exclusion of Men who have Sex with Men from Blood Donation Position Statement: 12th March 2009; National Health Service of the United Kingdom,
Summary of International Policies relating to the Exclusion of Men who have Sex with Men from Blood Donation (March 2009); and Medscape Today,
Debate Continues Over Blood Donation From Men Who Have Sex With Men 27 Feb 2009. I believe countries in the Caribbean have a similar restriction. In some countries, the person is only barred if he had sex with another man since ~1977. In others countries, the bar is not permanent and it may apply to the female sexual partners of MSMs. For example, the NHS document on international policies says that the bar in Australia is for 1 year since the last sexual encounter and applies both to MSMs and their partners (including women) and the bar in New Zealand is for 5 years since the last encounter.
5. UNAIDS (2008). Report on the global AIDS epidemic. UNAIDS, Geneva. p. 53
6. ibid, p 54
3. Not that many people in the Caribbean have HIV.You may be accustomed to hearing that the Caribbean has the second highest HIV rate in the world, a rate second only to that of sub-Saharan Africa. Well, that's true. But have you ever wondered what the figures are? Is it that we're really close to them? Are we close but are both figures really that high? And what's our HIV rate?
The Caribbean's adult prevalence rate stands at 1.1%, just over one fifth of Sub-Saharan Africa's 5.0%. The world average is 0.8%. [1] By country, our adult prevalence rates range from a low of 0.1% in Cuba to a high of 3.0% in the Bahamas with notable mentions of Haiti at 2.2%, the Dominican Republic at 1.1%, Jamaica at 1.6% and Trinidad and Tobago at 1.5% [2]. (SVG's rate in the general population is at least 0.4% [3]. Not all countries report their prevalence rates; you can download your country's report
here to see if it's given in the report.) Sub-Saharan Africa's rates range from less than 0.1% in the Comoros to 26.1% in Swaziland with notable mentions of Botswana at 23.9%, Lesotho at 23.2% and 4 other countries with rates over 15%. [4]
As you can see, although we're the second worst-hit region, the epidemic in Africa is considerably worse than the epidemic in the Caribbean.
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1. UNAIDS (2008). Global facts and figures 2008. UNAIDS, Geneva.
2. UNAIDS (2008). Report on the global AIDS epidemic. UNAIDS, Geneva. p. 230
3. St Vincent and the Grenadines UNGASS report, p 5.
Internet link. The prevalence rate was clearly calculated by dividing the 472 reported cases by the 106,253 persons living in the country according to the census so it doesn't take into account those people who have HIV but haven't been tested for it. Since we don't have universal testing for HIV, this means that this figure is certainly too low.
4. UNAIDS (2008). Report on the global AIDS epidemic. UNAIDS, Geneva. pp 39, 215
4. HIV/AIDS prevalence statistics have been revised downwards several times in the past. The Caribbean's measurement and surveillance are generally poor in almost every area that matters, but it seems that we aren't the only ones with problems when it comes to estimating the impact of HIV and AIDS in populations. Since most (all?) countries in the world do not have universal testing for HIV, statistical techniques are often [1] used to make educated guesses of the HIV prevalence rates of entire populations based on the rates of people who are tested. These techniques aren't always as accurate as we'd like them to be. In November 2007, there were widespread
reports of UNAids having to readjust and revise statistics of the prevalence of HIV/AIDS downwards in several places around the world because of significant errors in the statistical models used to estimate national prevalences. (This is probably not usually UNAIDS' fault; the organisation can only go on the data it receives from governments and other partners.) The reports centred on a revision of the Indian estimate by 7 million people and on revised estimates in some African countries, but by looking at the UNAIDS reports over the years, it seems that the Caribbean is also one of the places where figures had to be adjusted.
UNAIDS has issued a global report on the HIV/AIDS epidemic at the beginning of every even year since 1998. The organisation also issues epidemic update reports at the end of every odd year. One only has to look at the figures for the 2003 epidemic update report and the 2005 epidemic update report to see that something is amiss. The 2003 report numbers the Caribbean's general HIV population as somewhere between 350,000 and 590,000 people with an adult prevalence rate between 1.9% and 3.1% [2]. The 2005 report revised these figures for 2003; it gives a general HIV population of between 200,000 and 510,000 with an adult prevalence rate of between 1.1% and 2.7% [3].
One can also see downward revisions of figures in the prevalence rates of some countries. In the Caribbean, the global reports have only consistently reported country statistics for the Bahamas, Barbados, Cuba, the Dominican Republic, Haiti, Jamaica, and Trinidad and Tobago. I'll take three of them to make my point, but you can check the statistical tables at the end of the reports to see the others. The percentage given in normal type is the percentage that was given by that year's report. The italicised rates in parentheses are revised rates given in a 2008 WHO/UNAIDS document on the history of the epidemic from 1990 to 2007 [4].
Haiti: 2001 6.1% [
2.2%]; 2003: 5.6% [
2.2%]; 2005: 3.8% [
2.2%]; 2007: 2.2%.
Bahamas: 2001 3.5% [
3.1%]; 2004 3.0% [
3.0%]; 2005: 3.3% [
3.0%]; 2008: 3%.
Trinidad and Tobago: 2002: 2.5% [
1.4%]; 2004: 3.2% [
1.4%]; 2006: 2.6% [
1.5%]; 2008: 1.5%.
In each case, you can see that the current estimates are significantly lower than the estimates before 2008. This is most pronounced for Haiti and least pronounced for the Bahamas. Given Haiti's large population, it seems that the overestimates in Haiti are partly to blame for the bloated regional figures in the earlier reports.
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1. Often but not always. For example, it seems that Barbados, Trinidad and Tobago and Jamaica use such techniques, but at least some of the nations of the OECS don't. The calculation of SVG's 'prevalence' rate as note in point 3 of note 3 above suggests that SVG does not use such statistical techniques.
2. UNAIDS (2003). AIDS epidemic update 2003. December. UNAIDS, Geneva. p. 5
3. UNAIDS (2005). AIDS epidemic update 2005. December. UNAIDS, Geneva. p. 53
4. Figures for the normal type rates are from the UNAIDS 2002, 2004, 2006 and 2008 global reports, pages 198, 203, 530 and 230 respectively. Figures for the italicised rates are from
Adult (15-49) HIV prevalence percent by country, 1990-2007, a WHO/UNAIDS document.
5. A study found that, genetically, black people tend to be more susceptible to HIV than people of other races.
A study released last year reported that a gene that protects black people from malaria also increases their vulnerability to HIV infection by about 40%. Strangely, this same gene apparently allows those people to live an average of two years longer than HIV-positive people without the gene. About 90% of Africans and 60% of African-Americans possess the gene. I have no idea what proportion of Afro-West Indians or people of other races have the gene.
As far as I know, this is the first and only study that has found anything like that. It hasn't been confirmed by other studies as yet, so it isn't quite scientific fact just yet.
UPDATE: A follow-up study[4] attempting to confirm the results of this first study[5] found evidence contradicting the first study. The second study's researchers found that there was no difference in HIV susceptibility or AIDS progression in people who possessed the supposed gene. While I saw news of the first study in the media, I'm yet to see anything on the second study. Many thanks to Meisha Bynoe for alerting me to this follow-up study.
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1. BBC News. "Malaria gene 'increases HIV risk'". 16 July 2008.
http://news.bbc.co.uk/2/hi/health/7509210.stm2. The Washington Post. "Genetic Trait Boosts AIDS Risks in Blacks". 16 July 2008.
http://www.washingtonpost.com/wp-dyn/content/article/2008/07/16/AR2008071601539_pf.html3. MedPage Today. "Anti-Malaria Mutation in Blacks Promotes HIV Infection." 16 July 2008.
http://www.medpagetoday.com/HIVAIDS/HIVAIDS/101414. Winkler, Cheryl A et al. (2009). "Expression of Duffy Antigen Receptor for Chemokines (DARC) Has No Effect on HIV-1 Acquisition or Progression to AIDS in African Americans."
Cell Host Microbe. 2009 May 21; 5(5): 411-413.
ScienceDirect Link. You'll need to have an institutional login, connections or money to retrieve it.
5. He, Weijing et al. (2008). "Duffy Antigen Receptor for Chemokines Mediates trans-Infection of HIV-1 from Red Blood Cells to Target Cells and Affects HIV-AIDS Susceptibility."
Cell Host Microbe. 2008 July 17; 4(1): 52–62.
PubMed Central Link to entire document.
6. There are people who are resistant to HIV, there are people who seem immune to HIV, and there's this one guy whose doctor has apparently cured him of HIV....
Researchers have long observed that some people seem uncommonly resistant or even immune to HIV. It is now believed that certain genetic combinations confer virtual immunity to HIV, other combinations heighten resistance to HIV, and still others prolong the life of HIV-positive individuals by slowing the progression of AIDS. Knowing this, when an American man living in Germany who had been HIV-positive for 10 years needed a bone marrow transplant to treat his leukaemia, his doctor sought and found a compatible person who possessed the immunity gene. (White blood cells are produced in bone marrow.) It has been over two years since the man's transplant and he now seems to be HIV-free.
Unfortunately, this procedure is fairly expensive and rather dangerous. It is only used as something of a last resort to treat leukaemia patients and, even then, it kills up to 30% of the people it is used on.
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1. Wired. "Genetic HIV Resistance Deciphered" 7 January 2005 (or is that 1 July 2005?)
http://www.wired.com/medtech/health/news/2005/01/66198?currentPage=all2. The Independent. "Gene therapy offers hope of cure for HIV". 12 February 2009.
http://www.independent.co.uk/life-style/health-and-families/health-news/gene-therapy-offers-hope-of-cure-for-hiv-1607227.html3. The Wall Street Journal. "A Doctor, a Mutation and a Potential Cure for AIDS: A Bone Marrow Transplant to Treat a Leukemia Patient Also Gives Him Virus-Resistant Cells; Many Thanks, Sample 61". 7 November 2008
http://online.wsj.com/article/SB122602394113507555.html7. Male circumcision significantly reduces the risk of men contracting HIV.
Several studies have found that male circumcision reduces the risk of sexual transmission of HIV from a woman to man in penile-vaginal intercourse by about 60%. As a result, the WHO and UNAIDS now recommend its use as part of the package of HIV-fighting measures [1]. Research is currently unclear on the impact of male circumcision on the sexual transmission of the virus from male to female and on its effect on transmission to the insertive partner in anal intercourse. Studies so far suggest that male circumcision does not significantly reduce HIV transmission in male to male sexual transmission [2].
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1 UNAIDS. "Male circumcision."
http://www.unaids.org/en/PolicyAndPractice/Prevention/MaleCircumcision/default.asp
2. BBC News. "Circumcision HIV impact doubted". 7 October 2008.
http://news.bbc.co.uk/2/hi/health/7656229.stm.
8. There's evidence that condoms may negatively interact with other anti-HIV/AIDS strategies.
This one is a tip back to
the entry I made about that controversy the Pope got into in Africa some time ago. This time, though, I'll skip the Pope stuff and go straight into what the scientists on his side said. This is a repeat of what I said in that note.
The Irish Times[1] quotes Dr. Edward Green[2], the director of Harvard's HIV Prevention Research Project, as saying that "
there is not a single country in Africa where HIV prevalence has come down primarily because of condoms". He claims that many of the reductions in African HIV/AIDS rates are because of reductions in the number of sexual partners that Africans have. The Catholic news Agency quotes him more extensively and even has him saying -- in some appropriately fancy scientific language, of course -- the same thing that some regular people argue: that condom use may increase risky behaviour[3].
And he isn't the only one. In 2003, Norman Hearst, a Professor at the University of California, San Francisco published a study on the effect of condom promotion on AIDS prevention in the developing world[4]. The study's summarised results:
Condoms are about 90% effective for preventing HIV transmission, and condom use has grown rapidly in many countries. Condoms have produced substantial benefit in countries like Thailand, where both transmission and condom promotion are concentrated in commercial sex, but the public health benefit of condom promotion in settings with widespread heterosexual transmission remains unclear. In countries like Uganda that have curbed generalized epidemics, reducing numbers of partners appears to have been more important than condoms. Other countries continue with high HIV transmission despite high condom use. Impact of condoms may be limited by inconsistent use, which provides little protection, low use among those at highest risk, and negative interactions with other strategies, such as partner reduction.There are, of course, more than two people in the epidemiological community. In the CNA article Dr Green plainly says that his views aren't popular. But that, of itself, doesn't render them without merit.
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1. Irishtimes.com. "Harvard director backs pope on condoms". 30 March 2009.
http://www.irishtimes.com/newspaper/world/2009/0330/1224243690652.html2.
His profile page on the website of the Harvard AIDS Prevention Research Project.
3. Catholic News Agency. "Harvard Researcher agrees with Pope on condoms in Africa". 21 March 2009.
http://catholicnewsagency.com/new.php?n=154454. Hearst, Norman and Chen, Sanny.
Condom Promotion for AIDS Prevention in the Developing World: Is it Working? 26 March 2003
http://www.usp.br/nepaids/condom.pdf9. Your 'epidemic' probably isn't your epidemiologist's.
When most people hear the word 'epidemic' they think of a rapidly-spreading, deadly disease that infects a large proportion of the population in a region. They then understand a 'pandemic' as an epidemic that is widely distributed geographically, such as across continents or around the world. This seems to be a good description of the casual, non-scientific use of 'epidemic', but as the issue with H1N1 (
swine flu) and raising the world flu pandemic level hinted at [1], it isn't the really
the definition of epidemic. In fact, it isn't the definition that health officials mean when they talk about the AIDS epidemic.
One technical definition of an epidemic is "
the occurrence in a community or region of cases of an illness, specified health behaviour, or other health-related events clearly in excess of normal expectancy; the community or region, and the time period in which cases occur, are specified precisely" [1]. The article I got that definition from goes on to point out that "the definition does not specify a minimum number of cases. The area covered by an epidemic may be limited to a small area such as a school classroom, or it may extend to include many countries. Epidemics may also last from a few hours to many years." Note also that the definition says nothing of the severity of the disease.
Note also the key phrase "...in excess of
normal expectancy..." (emphasis mine). I don't know how it is defined and who defines it, but it seems that 'normal expectancy' -- what is considered a normal incidence rate for a disease -- depends on the disease being described. For a disease with an expected incidence rate of 25%, 50% would exceed normal expectancy; for a disease with an expected incidence rate of 0.1%, 1% would exceed normal expectancy. So while the word 'epidemic' tells us that the incidence of a disease is worryingly high, it doesn't tell us anything about the severity of a disease, nor does it tell us what proportion of the population has it.
I haven't been able to find out for sure what is considered normal expectancy for HIV or AIDS. Google has quite failed me there v_v. The only thing I've found is a reference in the 2004 report on the global aids epidemic to a generalised epidemic being where HIV prevalence is above 1% [3]. Is it still defined as that? If I had to guess I'd guess 'yes', but I really have no idea. Does this mean that a specialised epidemic in, say, women would be where their prevalence is over 1%? Once again, I'd guess 'yes' here, but, once again, I really don't know.
And does this mean that if our prevalence rate were only 0.4% it would be incorrect to say that there's an HIV epidemic in the general population of St Vincent and the Grenadines?
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1. I'm referring to the WHO's consideration of a flu pandemic purely in terms of how widespread the disease is without regard for its deadliness.
This BBC News article hints to that and also talks about concern for the panic that declaring a flu pandemic might have caused. Check also
the WHO's own pandemic scale, which says nothing about deadliness, and
talk of devising a flu pandemic severity index in the US.
2. Green, MS et al. When is an Epidemic an Epidemic? Israel Medical Association Journal 2002; 4: 3 - 6.
http://www.ima.org.il/imaj/ar02jan-1.pdf. This is a short, easy read on the different ways different people use the word 'epidemic' and the impacts those differences may have.
3. Page 24. The sentence, "By 2002, only 36% of low- and middle-income countries had a fully implemented surveillance system; however, 58% of countries with a generalized epidemic (where HIV prevalence is above 1%) had such a system."
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Some UNAIDS publications
AIDS epidemic update report archive2001 AIDS epidemic update2002 Report on the global AIDS epidemic
2003 AIDS epidemic update2004 Report on the global AIDS epidemic2005 AIDS epidemic update2006 Report on the global AIDS epidemic2007 AIDS epidemic update2008 Report on the global AIDS epidemic