The Spread of AIDS: How a silent killer devastated America, and what we can learn from it.
It’s 1980, and flight attendant Gaëtan Dugas is visiting New York City. He is a well-traveled man, routinely flying between the west and east coasts, and internationally. A prolific member of the local gay scene and an avid partygoer, Gaëtan enjoys himself before leaving on a return flight to LA. Unbeknownst to him, an at the time unnamed disease is coursing through his veins: Human Immunodeficiency virus. Although he likely contracted the disease in Haiti many years ago, Gaëtan is asymptomatic. It will be 4 years until he dies from AIDS, by then having spread the deadly virus to thousands of gay men around the country. He is patient zero of the AIDS epidemic in america.
Or so the story goes…but the truth is much more complicated.
Gaëtan Dugas, long known as the infamous AIDS “patient zero”, died before the retroviral agent causing AIDS was identified. He didn’t live long enough to see the publishing of a study which connected him to numerous AIDS clusters on both coasts, or read the 1987 book by Randy Shilts which misconstrued the study’s findings to mean Gaëtan was the source of those outbreaks. What Gaëtan did know was that he had supplied critical information to scientists frantically trying to track the spread of a deadly, invisible disease. He supplied them with a list of sexual contacts accumulated over the course of years, allowing the researchers to build an infection model which allowed them to build a network detailing past victims of the disease and potential future victims. Without the information from Dugas, it likely would have taken months or even years longer for the first transmission network to be built. At the time, with so much unknown about HIV, being able to track its spread with reliability was one of the few victories scientists could proclaim. The same process was mirrored in the early stages of the coronavirus pandemic, as contact tracers worked frantically to identify the pathways of transmission in order to understand the vectors the virus used to jump from person to person.
Figure from the 1984 paper in the American Journal of Medicine, incorrectly identifying Dugas as “patient zero” in a network of AIDS cases.
32 years after the study which led to his infamy, Gaëtan Dugas was exonerated with the use of modern genomic techniques and historical analysis. AIDS has a much longer incubation period than 10 months, contrary to the beliefs of medical scientists in the 80s. Many of Gaëtan’s contacts had already been infected, and sequencing of his particular strain of HIV from blood samples showed that it was not the precursor to dominant strains of the virus. In reality Gaëtan was a victim of sampling bias in a time when gay men would rarely be as forthcoming with personal information as he was, leading scientists to overestimate his influence in the historical spread of AIDS. The disease had been circulating in Africa since at least the 1920s, likely making the jump to the caribbean in the early 60s and from there to the continental United States. Furthermore, retrospective analysis of suspected historical AIDS victims and modern statistical techniques reveal that there were multiple “index cases” in America, as the disease jumped multiple times in isolation from the caribbean to the continent. Interestingly, the predominant strain of the virus (HIV-1) in America is indeed thought to have traveled to the new world through a single unidentified Haitian man.
While the efforts of epidemiologists certainly saved thousands of lives, many mistakes were made in the early years of the epidemic. Infamously, early CDC reports hinted that the disease could be passed by casual contact as well as bodily fluids, leading to a lasting stigma against HIV patients which often resulted in lower treatment standards and reduced priority. The disease was also widely known as the “Gay Plague” despite the fact that scientists had proven it could be transmitted through heterosexual sex and from mothers to infants. While this cultural prejudice certainly contributed to a lack of funds and coordination in the fight against AIDS, it also stymied efforts to educate the heterosexual public about the dangers of the virus and the necessity of safe sex. It was only until a series of high profile contractions of HIV in the 90s that the public began taking the disease seriously and more attention was devoted to combating it. Critical mistakes were also made in the contact tracing process, such as the assumption that the infected would display symptoms according to a standard model of disease progression, or that people couldn’t be infected multiple times with the disease. These lessons must be incorporated into efforts to track and curtail epidemics around the world if we are to fight global disease going forward.
Despite early mishaps and cultural stigma, HIV has been steadily declining in both mortality and infection in recent years. Decades of efforts such as safe-sex education, needle safety awareness, blood testing, and more have enabled scientists to control one of the most deadly pathogens in existence. What once was a death sentence now as a survival outlook equivalent to the average life expectancy (provided the disease is caught at an early stage). With the advent of economic and reliable blood tests, the chances of infecting a newborn with HIV during childbirth is historically low. Although the fight is not anywhere close to being over, and it may still be decades more until a comprehensive sure is developed, the fight against AIDS may be called a rare victory in the history of disease prevention. The success of the tactics used in these campaigns should be readily applicable to other similar efforts, such as containment of the novel coronavirus. Tactics to reduce the spread of the virus such as quarantining and mask wearing have already been implemented to great effect, but as in the case of Gaëtan Dugas it should be remembered that simple solutions and explanations often miss important details. HIV is known to produce viral reservoirs in the tissue of infected patients, which even if suppressed with antiviral drugs may become reactivated later in life if the patient stops taking medication. Research is already being done into the potential for the novel coronavirus to display similar behavior. The prevalence of asymptomatic carriers of the disease was and is a large contributor to its spread, as early testing efforts often relied solely on temperature and visible symptoms rather than RNA analysis. The same was true in the early years of AIDS as unknowing carriers transmitted the disease for years before showing symptoms themselves.
In the simple branching process model (R0=pk) the two ways to stop an epidemic are to reduce “p” (probability of infection upon contact) or reduce “k” (number of connections between people). Both of these tactics have been used in the AIDS campaigns and coronavirus prevention. however scientists must be aware and vigilant of the implications seemingly minor mistakes can have on the public consciousness. Often enough, as in the case of AIDS, faulty messaging can backfire and hamper containment efforts or increase the negative effects of the disease. Social awareness and qualitative design must be maintained going forward if we are to learn from the mistakes of our past.
Sources:
https://ourworldindata.org/hiv-aids
https://www.avert.org/professionals/history-hiv-aids/origin
https://www.avert.org/professionals/history-hiv-aids/overview
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884281/
https://www.nytimes.com/2016/10/27/health/hiv-patient-zero-genetic-analysis.html
https://www.vox.com/2015/12/1/9814026/world-aids-day-2015-hiv-awareness
https://www.healthline.com/health/hiv-aids/life-expectancy