Sickness is the state of being unhealthy. In Fate of the World, a person is considered sick if they have any serious illness or injury that effectively cripples them and prevents them from working. The amount of sick people in the region are indicated by the Sick percentage in the region's statistics.
- Emissions play a major role in the overall health of a region as well as the world as a whole. As air quality declines, chronic problems like cancer become prevalent and significantly lead to more bed-ridden workers.
- Population also contributes to overall health. As a region grows too big or too quickly, the number of healthcare facilities usually become insufficient. This will be indicated by News Reports, which will repeatedly talk about overcrowded hospitals and poorly-treated patients.
- The region's GDP indicates the level and quality of healthcare available to the public; Europe will have modern, first-class hospitals, but North Africa will have poor, outdated ones. Regions that suddenly become poor (usually from a financial crisis) will often rapidly become unhealthy as its healthcare system is forced to make cutbacks.
- In a region's statistics, the Sick percentage is subtracted from the amount of Workforce (adults) in the region to indicate the region's Workforce (adults who can work). Because of this, the more sickness there is in a region, the fewer able workers it has. Thus, sickness reduces a region's GDP and production.
- Sickness raises a region's Mortality Indexes, which lowers the region's Life Expectancy, which lowers the region's HDI.
- Support and Contentment is increasingly lost as more of the population is crippled from sickness.