One of the possible world-ending disasters is a global disease pandemic. Depending on how infectious the disease in question is, it could affect the world population in a matter of days to a matter of weeks or months. In heavy population centers, the disease will spread faster. There are certain things that can help you avoid infection.
In the case of most diseases there is a percentage of the population that will be unaffected by a particular disease. While there is nothing you can do to make yourself immune (unless you’re a brilliant doctor with access to a lab), it is the best defense against disease. That being said, we are talking about disease. Whether viral or bacterial, it is likely to mutate at some point, if this happens it’s possible that those that were previously immune are no longer immune. Because of this, it’s best to adhere to the following suggestions in order to avoid infection regardless of immunity.
The most likely way to contract the disease is through contact with others. The logical solution, then, is to avoid people as much as possible. If you can’t avoid contact with others, try to avoid physical contact or getting too close to them.
In the case that you cannot avoid contact with other people, you should wear some kind of protective gear to prevent infection. Disease are spread on many different vectors. Your best bet is to wear a biohazard protective suit. These suits essentially negate the fact that you were in contact with someone else. However, in the case that you don’t have one of these suits, you can wear a respirator to block airborne pathogens, or you can wear glasses or goggles and medical gloves to protect against contact pathogens.
Your mother always nagged “Wash your hands before you come to dinner!” for good reason. You have no idea what you’ve been exposed to throughout the day and you could end up with a pathogen on your hands. This is a good practice regardless, since you don’t know what nasty little things you may pick up on your hands and in a post-apocalyptic world like this you can’t rely on doctors to cure something we consider trivial nowadays.
Following these steps won’t guarantee you stay safe from viral infection, but it can increase your chances of safety.