Everything you mentioned was neither fact or scientific.
But....germ theory is correct despite it still being a theory. it was first considered following Semmelveis and also the first epidemiologust Jon Snow and the Broad street pump's cholera epidemic. It was only recently confirmed for sure when we could see and detect the pathogens with instruments. But it is still called a theory. Does that mean it can be wrong? Of course not!
What science is, what facts are, what theories are, what evidence is.....these are the misconception many people are left with following a religious indoctrination, I certainly was.
If something was learned via a scientific approach (i explain it below), it becomes evidence, the theories are constructed solely based on the evidence, but is only subject to change based on more evidence that ADDS to the theory. This is progress, this is how we have advanced so much in the last 150 years. There is no shame in moving on with our knowledge. Adding to our knowledge is not a weakness and in no way states that we could be wrong about everything, simply that we could have a lot more to learn about everything!
Germ theory is true and can never be false or changed, however we can learn more about its mechanisms and so it remains a body of knowledge, a theory.
This is not to be confused with previous false ideas that people had in history, they had nothing to do with science!
Also there are very few scientific facts, a good one example may be the earth being round, that the earth goes around the sun currently etc. Again, do you really believe there is a possibility that these things are wrong? Of course they are not!
But atoms, gravity, evolution, even germs.... are all a theory, that is a body of evidence collated together. We have more evidence for explaining evolution than we do for gravity. Will you deny gravity? Want to chance we are wrong about it by hopping off a cliff?
What is science?
science is information gathered by research conducted using the scientific method, a 5 stage process that eliminates as much human bias and error as possible. That's it! That is all science is. Those things you listed.... Were they learned via science? No!!
Non scientists especially with a religious background, will list things such as the earth being flat as examples of science being wrong in the past, or as you just did, suggesting that there were many wrong ideas about what caused disease......these ideas were neither scientific or facts. I used to make the same mistake myself.
Secret Heart, if a conculsion was reached without using the scientific method.....it wasn't science! The scientific method was first penned properly by Francis Bacon only about 200 years ago. Now, all research is measured for its legitimacy against that standard. If it doesn't measure up it is dismissed until it is done properly. This is what has brought us from horse and cart to space stations in less than a hundred years!
Evolution is something we can witness in a lab, we can even manipulate evolution in the real world! Big bangs are also something we can make in a lab, we also can see, hear snd witness it's effects in the real world. These things won't be and can't be reversed.....
A fact is something we know for sure, germ theory is still a theory but we know for s fact germs exist, same goes for atomic theory, the theory of gravity and the theory of evolution etc etc etc...