[Question] What are some interventions before 1920 that improved human well-being 100 years later?

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