Hello historians,
What are some interventions before 1920 that improved human well-being 100 years later?
For examples:
- Holden Karnofsky cited United States Hookworm reduction starting around 1909.
https://www.openphilanthropy.org/research/philanthropys-success-stories/
https://en.wikipedia.org/wiki/Hookworm_infection#Eradication_programmes
- Jason Crawford cited Smallpox inoculation before 1700 and vaccination starting around 1796.
https://rootsofprogress.org/smallpox-and-vaccines
This is a bit of an amorphous question with tons of possible answers in some sense—e.g., the development of the scientific method—but actually identifying counterfactual benefits is tricky. The examples you listed probably don’t have major counterfactual benefits long into the future.
Seems unlikely for these examples. It's not the scientific discovery that really matters; it's the public health program implementing it, which is a lot more sensitive to pre-existing conditions than discovering a fact about the world is.