Today has seen a flood of press stories about a new study which strongly suggests that HIV-1 subtype B migrated into the US from Central Africa by way of Haiti. The stories were instigated by a press release from the University of Arizona, publicizing a paper by Michael Worobey and colleagues which is apparently due for online publication in PNAS later this week. Rather awkwardly, the paper does not seem to be online as yet (UPDATE 10/31: the PNAS article is now online, although to the journal's discredit they have not made it open access. UPDATE 11/1: I guess I wasn't the only person who thought the paper should be open access, to their credit PNAS has now made the PDF available free of charge). Anyone interested in finding out more details about the study can watch Michael Worobey's presentation at CROI earlier this year; just go to the webcast page and then scroll down to the session entitled "Oral Abstracts: Epidemiology: Transmission Dynamics and Risk." Click on "Play Video" and Worobey's presentation is the first in the session.
Sadly, the study is re-igniting controversies regarding Haitians somehow being blamed for HIV (as happened, with horrible consequences, in the early 1980s). You can hear an angry response to Worobey's presentation by a Haitian researcher at the end of the CROI webcast, and Jean Pape is quoted in an article in Science by Jon Cohen saying that the study authors "restate prejudices advanced 2 decades ago." However, it seems clear that the researcher's interest is in using molecular techniques to track the history of HIV's spread, not in judging any person, nation or ethnicity. Some press stories have highlighted the suggestion that one transmission event from Haiti around 1969 triggered the US epidemic, and made the leap that - if true - the individual in question must have been Haitian. But the study makes no such implication; only that the genetics of early HIV sequences provides strong evidence that the virus circulated in Haiti prior to the US and that a single transfer event occurred; if a single individual did transfer the virus between the countries, they could have been of any ethnicity and the transfer was almost certainly an inevitability. The study authors do suggest that it might have been an infected Haitian worker returning from the Congo that transferred HIV from Africa to Haiti around 1966 but this is speculation; the molecular data supports the hypothesis that the virus moved between those two places around that time but says nothing about how the transfer occurred. It is dismal to realize that the stigma associated with HIV because of how it is transmitted remains strong enough to severely complicate the discussion of this type of study in 2007.
The Emergence of HIV/AIDS in the Americas and Beyond
Gilbert MTP, Rambaut A, Wlasiuk G, Spira TJ, Pitchenik AE & Worobey M
(2007) PNAS In press
HIV-1 group M subtype B was the first human immunodeficiency virus discovered and is the predominant variant of AIDS virus in most countries outside of sub-Saharan Africa. However, the circumstances of its origin and emergence remain unresolved. Here we propose a geographic sequence and timeline for the origin of subtype B and the emergence of pandemic HIV/AIDS out of Africa. Using HIV-1 gene sequences recovered from archival samples from some of the earliest known Haitian AIDS patients, we find that subtype B likely moved from Africa to Haiti in or around 1966 [1962-1970] then spread there for some years before successfully dispersing elsewhere. A ?pandemic? clade, encompassing the vast majority of non-Haitian subtype B infections in the US and elsewhere around the world, subsequently emerged after a single migration of the virus out of Haiti in or around 1969 [1966-1972]. Haiti appears to have the oldest HIV/AIDS epidemic outside sub-Saharan Africa and the most genetically diverse subtype B epidemic, which might present challenges for HIV-1 vaccine design and testing. The emergence of the pandemic variant of subtype B was an important turning point in the history of AIDS but its spread was likely driven by ecological rather than evolutionary factors. Our results suggest that HIV-1 circulated cryptically in the US for approximately twelve years before the recognition of AIDS in 1981.
The Association of Haitian Physicians Abroad (AMHE) responds to Worobey study, November 7, 2006
The Association of Haitian Physicians Abroad (Association des Médecins Haitiens à l'Etranger or AMHE) has reviewed the recent article by Thomas Gilbert and colleagues, reporting a phylogenetic analysis of archival blood samples collected from five early recognized AIDS patients at Jackson Memorial Hospital in 1982-1983.
The study authors identify these five patients as Haitians who left Haiti after 1975. This article has several important limitations and does not provide any scientific breakthrough. Before a detailed critique of this paper, AMHE would like to point at the following remarks in methodological biases that may explain some of the study findings. First, the bias in selection of early samples of HIV among Haitians is quite obvious. The investigators chose a convenient sample under the unproven assumption that all these Haitian immigrants acquired HIV infection in Haiti. They obviously ignore that the clinical course of these patients perfectly fits the natural history of HIV/AIDS. No culturally-sensitive epidemiological investigation has ever been conducted of these initial Haitian immigrants presenting with HIV infection at Jackson Memorial Hospital in Miami. Therefore, the assertion that they contracted HIV in Haiti is presumptuous and not based on facts. Moreover, no archival samples from Haiti are included in the phylogenetic analysis and this constitutes a serious flaw. We do not know either how many samples of the pandemic clade B might have come from Haitian subjects, which raises the prospect of misclassification.
Second, the authors do not adequately report on some of their methods and results. For example, they do not specify clearly the number of sequences for which there was uncertainty as to which subtype they belonged to; neither do they try to replicate their results by sequencing other HIV genes. While computer simulation techniques and phylogenetic analyses are important to our understanding of biological evolution, the application of these methods with such serious methodological limitations does not prove unequivocally the origin of the pandemic clade B subtype in the United States.
Because these findings lack scientific validation, we need to raise questions about the motives of the authors; their paper not only does not advance our knowledge of the HIV epidemic but it continues with a dangerous precedent of victimizing an ethnic group with flimsy data. Needless to say that such half truths have been very harmful to the country and its people. The hasty classification of Haitians as a group at risk for HIV more than 20 years ago can be considered as a cloud hanging over good scientific practice. It destroyed the tourist industry in Haiti; its citizens have since been suffering from the social stigmata of presumed carriers of dangerous germs even though that classification was finally removed by the CDC.
We are also afraid that such mishandling of data can have the unintended consequence of the refusal of Haitian patients to participate in research studies at American Universities for the fear that they will be used as guinea pigs in the furtherance of biased scientific protocols and conclusions. That would be the saddest of ironies for we all need good science to help us all against this calamity.
La Science sans conscience n'est que ruine de l'âme.
Christian Lauriston, MD
President of the Central Executive Committee of AMHE.
Posted by: Stanley Lucas | November 08, 2007 at 01:34 AM