TL;DW:
Due to various molecular configurations (aka polymorphs), currently known medicines when contaminated with a catalyst seed molecule/particle can become unstable and irreversibly unreproducible via chained-contaminations.
This system of contamination and reproduction acts in similar fashion to viral infections.
Current Solutions:
- better clean room procedures for all steps of medicine manufacturing.
- pour more money into medicine polymorph research.
The video is about polymorphism. Both tin pest and the drug incident that this video covers are instances of polymorphism where a less desirable polymorph is more stable. It goes into detail about similarities, differences and much more.