Scenarios about 'germ theory'

The scientific understanding that many diseases are caused by microorganisms too small to see with the naked eye, developed primarily in the 19th century. Pioneered by scientists like Louis Pasteur and Robert Koch, germ theory revolutionized medicine by establishing the foundation for modern hygiene practices, antiseptic procedures, vaccination programs, and antibiotic treatments, dramatically reducing mortality rates worldwide. In alternate history scenarios, delayed or accelerated development of germ theory significantly impacts public health outcomes and potentially changes the course of civilizational development.