The most recent common ancestor of the HIV-1 M group, responsible for the HIV pandemic, dates back to the Belgian Congo city of Léopoldville (modern Kinshasa), circa 1910. And the genetic history of the virus indicates that there have been several separate "jumps" of the virus from the simian version, SIV, dating back to possibly as far back as 1884, though evidence suggests that the true date is somewhere between 1908 and 1924. Bearing this in mind, I'd argue that we're definitely far closer to the best case scenario than the worse case scenario when it comes to HIV.

So, let's imagine this- instead of spreading from Kinshasa and being transmitted outside of West-Central Africa for the first time in 1952, as in our timeline, let's say that in a different timeline, a sexually prolific European picks up the virus from frequenting a brothel in Leopoldville in the early 1910s, then travels back to Europe to fight in WW1 on the Western Front, carrying it back to the military brothels there.

In our timeline, an estimated 20-30% of the entire population of Europe (including civilians) had been infected with syphilis by the end of WW1, with the STD transmitted to the population via these brothels and those who frequented them- a similar or even greater percentage of the population (once we add unsterile injections by medics and doctors to the mix, along with blood transmission), as much as a third of the total population, could have easily contracted HIV if it had spread from this timeline's 'patient zero' across Europe during WW1. And with anti retro-viral drugs still more than 70 years away, HIV had an 80-90% mortality rate.

Now, let's compare this scenario to the 1918 flu pandemic. That also infected roughly a third of the world population; however, it only had a mortality rate of 10-20%, 4-8 times lower than that of HIV. In other words, you'd have been looking at a projected death toll for this timeline's WW1 HIV pandemic which would be projected to be 4-8 times higher than that of the 1918 flu pandemic- and even worse, you'd have both pandemics coinciding with one another and spreading at the exact same time.

In our timeline's 1918 flu pandemic, current estimates say 50-100 million people worldwide were killed, 3% to 6% of the entire world population. In this timeline though, in the worst case scenario, even if we assume that both pandemics have no impact upon each other (i.e, that no extra people are affected compared to our timeline's flu pandemic, that HIV doesn't exacerbate the mortality rate of Spanish Flu and vice-versa), the death toll would be projected to be between 200-800 million people worldwide; 12% to 48% of the entire world population.

To put that into perspective, the realistic mid-estimate for the death toll of this worst-case scenario alternate HIV pandemic, 24% of the world population killed within 3 years (the maximum life expectancy for those infected with HIV, with no treatment available at this early stage), would be equivalent to, or worse than, the reduction of the world population by the Black Death pandemics over the course of more than a century.

So would this earlier HIV pandemic have constituted a plausible, hard-science historical apocalypse scenario? And what sort of dystopian post-apocalyptic societies would you envision developing in this timeline? Our timeline's Fascists and Communists were bad enough; how much worse might this timeline's equivalents wind up being?

  • $\begingroup$ Thanks to the introduction of powerful medication called antiretroviral therapy, or ART, and advances in understanding the disease, it’s now possible for HIV-positive men and women to live far longer than they used to be able to. Before these medications were introduced, in the mid-1990s, people with HIV typically developed AIDS in just a few years. And we're talking about an HIV pandemic more than sixty years before the very first antiviral drugs were developed. I already took that into account, and adjusted it accordingly. $\endgroup$ Jul 1, 2018 at 10:26
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    $\begingroup$ Minor quibble: Wartime transmission would seem limited to Europe, since North American and ANZAC troops didn't get to fly home on leave, You may need spreading events on other continents, too. Wartime transmission to a soldier in, say, 1916 would still lead to AIDS probably later than 1918. Here's an article lowering the transmissibility estimates a bit. And not all of the sexually-active population is hetero - gay and monogamous-hetero would be tough segments for HIV to break into (lower rate of spread during the period). $\endgroup$
    – user535733
    Jul 1, 2018 at 13:09
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    $\begingroup$ Like any question one can answer with opinion, but there exist plenty of data which can be used to answer this question. The epidemiology of HIV has been tracked like few other diseases. I was just too slow. Reopen. $\endgroup$
    – Willk
    Jul 2, 2018 at 0:56

2 Answers 2


It may looks strange, but HIV is, in this regard, less efficient than flu.

Flu is airborne: it is perfect for a rapid spread in a world where ships could still carry large amounts of people fast enough from point A to point B and happily spread toaward unsuspecting targets. And once it gets a hold of its target, symptoms rapidly incapacitate it.

HIV requires direct blood exchange: in this regard is not worse than other venereal diseases. It will kill a lot of people, like those diseases did, but since it is slower in acting, once symptoms are visible on the body, medics and authorities can start tracking it down to the closest to patient zero. Triage and precautions can be refined and applied better than with flu, which is also a mutant and can hit again regardless of precautions -that is why we need to vaccinate, to keep it at bay from the weakest targets (sick people, elders, kids and babies)

So no, the answer is: HIV wouldn't change a thing unless all soldiers on all fronts had had sex with infected people, coincidentially in the right time frame so that at the end WWI they got sick with AIDS as well

In regard to the Fascism, once it has been determined that sexual contact is directly involved, it will cause authorities to push for stricter laws regarding monogamy and racial purity, but the whole legal corpus would be unaffected for what the general fascist philosphy is concerned.

  • $\begingroup$ "HIV wouldn't change a thing"? I already stated that this was the projection for a scenario in which no extra people are affected compared to our timeline's flu pandemic; where HIV doesn't affect the mortality rate of Spanish Flu and Spanish Flu doesn't affect the mortality rate of those with HIV. And we're talking about the 1910s here, still in the earliest days of virology. Even with the 1918-1919 Influenza epidemic, they took 12 yrs to identify that it was caused by a virus. Reverse transcriptase's discovery's still 50yrs away. And HIV's far slower acting, with a far higher mortality rate. $\endgroup$ Jul 1, 2018 at 10:18
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    $\begingroup$ The first AIDS epidemic in USA was caused by the exceptional promiscuity encouraged in those years, combined with unprotected sex. To get the numbers you want, you'd also need a radical change in the sexual habits of early 20th century. The only places where this thing could start would be the brothels, and given the AIDS' timeframe to reach near-terminal stage, again ALL future soldiers should have gone to bed with infected whores, coincidentially, 5 years before going to the front! You just can't have the numbers you want $\endgroup$ Jul 1, 2018 at 10:25
  • $\begingroup$ So then, back in the immediate aftermath of WW1, how could the medics and authorities possibly track it down to the closest to patient zero, when it'll take three years or more for symptoms to be visible on the body- time in which they could be spreading it to a whole host of people, and in which war medics'll themselves have been spreading it through needles and blood transfusions? And when that symptom of immunodeficiency means that those infected'll be dying of other diseases instead, how would they even identify HIV, given that the first human retrovirus wasn't discovered til 1980? $\endgroup$ Jul 1, 2018 at 10:33
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    $\begingroup$ just like they did with other venereal diseases when microscope didn't even exist! They examine the patients (and isolate the patients), list the symptoms, write down an anamesys and confront the data. Then you can start tracking down the sickness' progression $\endgroup$ Jul 1, 2018 at 10:42
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    $\begingroup$ And FYI, the first AIDS epidemic in the USA wasn't caused by hippies or free love; they were simply scapegoated for it. It was caused by a Haitian aid worker who visited the Congo and brought it back to Haiti with him in 1966, before a Haitian immigrant to Miami carried it with him (or her, given that sex trafficking was rampant) to the USA in 1969, where it circulated for roughly 12 years before AIDS was first recognized by scientists as a disease in 1981. And the transmission of venereal disease was rife in the trenches; not through sex, but blood transfusions and blood on broken skin. $\endgroup$ Jul 1, 2018 at 10:45

Mass HIV infection did not cause a population crash in pre-HAART subsaharan Africa.

The scenario you posit really happened and is happening in subsaharan Africa. Botswana has the third highest prevalence of HIV of any country and is the biggest of the top 3. 21.9% of the population is HIV+ and that has been fairly constant since 2000.

botswana hiv incidence and death

The problem for your mass dying scenario is that HIV really is very much like syphilis in Western Europe. It is not that lethal. A lot of people have it but not that many die. Considering pre-HAART rates, about 3-5% of persons with HIV die of it in any given year. Check out the unaids website liked above; it is a very nice interface for viewing the data.

death and incidence

This projection from 2000 noted that in the best case scenario, population growth in Botswana would just barely stay positive.


Botswana total population growth is declining rapidly due to HIV/AIDS. Only in the best case (S2) will growth remain positive (at 0.2%) by 2010. By 2010 the total population is projected to be between 1,53 million (S1) and 1.72 million (S2) • HIV/AIDS will profoundly alter the population age profile. The greatest reduction in numbers compared to a no-AIDS scenario by 2010 will be among adults aged 35-45 (a 40%- 50% reduction) and children aged 0-9 years (32-40% lower). • Under-5 and infant mortality will both increase. Under-5 mortality is expected to be 67-98/1000 higher than in a no-ADS scenario by 2005. The IMR will be 20-25/1000 higher than in a no-AIDS scenario in 2000, rising to a 24-33/1000 increase by 2005.. • Life expectancy is falling dramatically. It is projected to be only around half (46-52%) of no-AIDS scenario levels in 2010.

This best case came to pass. Population growth dropped but stayed positive in countries hit hard by HIV.

growth rate

population growth data for selected African countries

Positive population growth in this resource poor time and place means to me that your HIV scenario for Western Europe would not cause a plague like dieoff of the populace. HIV is like any other chronic endemic disease - like syphilis, or tuberculosis, or malaria.

  • $\begingroup$ But we're talking about an HIV pandemic more than sixty years before the very first antiviral drugs were developed. it's only thanks to the introduction of antiretroviral therapy that HIV-positive people can now live far longer than they used to be able to, and that the mortality rate greatly decreased. Before their introducion, people with HIV typically developed AIDS in just a few years, and without anti retroviral drug treatment, it's mortality rate was 80-90%. The population decline in Sub-Saharan Africa was arrested by its introduction. No such possibility exists in the 1920s. $\endgroup$ Jul 3, 2018 at 2:05
  • $\begingroup$ Protease inhibitors were invented in 1996 and not widely adopted in Africa for another decade. Look only at the pre-2000 prevalence and death rates. The death rate is a steady 3-5% of the prevalence rate. Even with a prevalence of 20%+ in the late 1990s as you posit for your scenario HIV was not enough to push population into decline for these countries. HIV+ women still conceive and raise children and the maternal-fetal transfer rate is only 25%. For a Black Death scenario you need a second plague that kills outright all the HIV infected. $\endgroup$
    – Willk
    Jul 3, 2018 at 14:44

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