The CDC recently updated survival rates (i.e., IF infected) for COVID-19:
0-19 yrs old: 99.997%
20-49 yrs old: 99.98%
50-69 yrs old: 99.5%
70+ yrs old: 94.6%
These rates are for all patients in the age range, regardless of factors like health conditions or immune compromise. It is reasonable to assume that previously healthy people are even more likely to survive infection with SARS-CoV2. In fact, the CDC model assumes that 40% of infected people are asymptomatic, meaning they would not notice a change in their health due to the virus.