Why do some people fall ill from SARS-CoV-2 while others infected with the virus experience no symptoms?
Why do some people develop neurological, cardiovascular or gastrointestinal symptoms while infection sticks to the respiratory system in others?
Since older age and underlying health conditions put people at greater risk of becoming seriously sick or dying from COVID-19, why do some young and otherwise healthy people barely survive the disease, while some elderly people with multiple risk factors weather it with only minor symptoms?
In addition to individual behavior, preexisting conditions and sheer luck, answers could lie in people's genes.