Answer:
Where to begin...First off, an obvious answer would be what disease was being discussed. Different diseases can vary in intensity for a variety of reasons. For example, let's say person 1 found out about his infection long before person 2? Person one will most likely have fewer and much less symptoms then person 2, and in some illnesses, may even be able to treat it in early stages. Let's say, however, that the disease was the same disease at the same stage for two different people. Resources could obviously effect the quality of life both have. While someone with a disease may be able to recieve medical staff, vaccines and machines that may allow them to recover with no issues, someone in africa may simply have to take it with no or little medical equipment, ultimetly putting their life on the line. The final thing I will discuss that is probably the biggest factor, genetics. Some people have immune systems strong enough to fight pretty much anything, while others could pass away from a cold. This has a major effect on quality of life, as the people with strong immune systems will be able to pretty much walk away from a disease with very few complications, while someone with a very weak immune system could walk away with weakened hearts, hernias, and in some cases, fatality.
Sorry the explanation was so long, but I do hope it's helped! :)
