Polio vaccines: wonderful lifesavers of the early 1950s!
But grown in monkey cells. Filthy creatures, monkeys.
The early vaccine developers went to great lengths to make sure their monkeys were clean and virus-free. (Because when you develop a vaccine, you're just manipulating large masses of virus particles -- and if there are local virus particles in your culture cells, they can come along for the ride.) By the time the Salk vaccine was ready to test, they'd found 39 different viruses... and had, with much difficulty, ensured their monkeys were free of them.
Almost 10 years later, it was discovered that they'd missed one.
Simian Virus 40 gave the small world of researchers a hell of a nasty scare. When first introduced into cultured monkey kidney cells, it caused them to clump up, lyse and die. When grown and injected into baby hamsters, it caused them to develop grotesque, massive tumors which killed them horribly. And by late 1960, it was clear that much of the world's supply of polio vaccines had been contaminated with SV40.
But in the end a scare was all it was. In the Salk vaccine (the injected one that used dead viruses) it seems that the process used to kill the polio virus killed most of the SV40 particles too. In the Sabin vaccine (the later one that used an oral solution of live but weakened viruses), the SV40 survived, but it seemed unable to penetrate the digestive tract. Most of all, SV40 seems to be either harmless or mostly harmless to humans. (There's some debate over whether it may have caused a small number of exotic cancers.) Anyway, by 1961 new monkey cell cultures had been developed, so all vaccines since then have been completely free of any viruses except the ones that are supposed to be there.
Okay, so. Let's say [handwave] that SV40 is deadly as hell. Say further that it's not inactivated by the Salk process; it just gets slowed down a bit. Now it kills slowly, so that symptoms don't appear for a decade. In other words, in this TL the panic that gripped vaccine researchers for a few months in 1960 turns out to be horribly well founded -- within a year or two, people will start dying, and by the mid-1960s they're dropping dead at the rate of several thousand per day in the US alone.
One estimate is that around 10 million Americans -- all ages, but disproportionately children -- were injected with SV40- contaminated Salk vaccine; in this TL, they're pretty much all going to die between 1964 and 1970 or so. We can throw in roughly the same number of Europeans, although now things get complicated because different countries took up the vaccine at different speeds -- the USSR, for instance, was slow to adopt the Salk vaccine and then shifted early and quickly to the Sabin oral one, so it'll come through a lot better.
Anyway. The generation born between 1950 and 1960 is going to be hit hardest; In very round numbers, we're going to kill off about a sixth of them. So, take any European or American born in this period and roll a die: on a 1, they're gone.
Thoughts?
Doug M.