If you think about it you would probably not notice it. Any type of bacteria is virtually invisible to the naked eye. We know that bacteria lives in every biotic and abiotic thing on this planet. Bacteria are in our every day life has adapted to or evolved just like humans. That is the key to all life on this planet being able to adapt or accommodate its surroundings. In the book Andromeda Strain the disease had come from outer space, that would be the most crucial and vital piece of information. To understand something you have to know what it is where it comes from and what compounds it is made up of.
The second thing that you have to recognize like in the case of the Andromeda Strain is if its compounds are earth like or if they are extraneous organisms from unknown reigns of space. You have to recognize what it is attracted to what it consumes and what if any waste it produces. This is very important to understanding how something works and survives. Although all of these steps would have to be taken in precautions steps in staying safe it would not be of use. The reason is because the Andromeda Strain had learned to adapt.
In considering the past this is very critical because the human population does not mind sharing its space things it can not see. There may have been many similar cases that have happened in our history that may have something to do with extraterrestrial life for example the common cold there is nothing common about it. Doctors are still confused about this nobody knows where or how long ago it came about. In retrospect, if Andromeda Strain had happened we probably would not have noticed. This would have been attributed to evaluation and the size of all bacteria.
We as a people accept what is told to us. The government would have made false claims to the Andromeda Strain to protect the human population from something that they did not need to know. These are things that will only make their lives more difficult and harder to understand. In theory if Andromeda Strain had happened life as we know it would go on just like it is now. That is why we are here now it is the ability to adapt to our environment. I think that in time the Andromeda Strain would have adapted enough that it would be beneficial to humans.