If you are a doctor/nurse working in a covid ward we know for sure that the risk whatever happens long term is a lot less than the risk of getting covid. For someone like me who has no reason to go anywhere (I'm not even allowed in the office until this pandemic passes) I can afford to wait until there is more data - and I also have to because I'm low on the list of those who will be vaccinated because I'm relatively low risk of getting it.
I vaguely remember this story (from years ago) about a drug or vaccine during the 70s, where apparently everything was fine but then kids (or kids of kids, can't remember) ended up with birth defects.
The name of the drug was "Contergan" in german which german-speaking readers might recognize more easily.
A more relevant example is Pandemrix, a flu vaccine launched in the EU in 2009. A year later it was discovered that it seems to increase the risk of narcolepsy in teenagers sixfold. The vaccine was produced and licensed in an expedited fashion because of a "pandemic" (of swine flu), which used a then-new and slightly experimental technique (adjuvants) which interestingly, German doctors flagged up as a risk and suggested the German government use a different H1N1 vaccine that was less experimental.
Given that viral genome sequencing didn't even exist in 1976, I don't think it's a meaningful comparison.
I've never heard of such a thing, but then again I have only a surface understanding of vaccines.