The Covid-19 coronavirus meets its most formidable foe the moment it enters the human body.
The immune system is waiting, ready for action, and it determines who dies and who survives. It is why the vast majority of the infected have recovered from the disease.
Yet one of the most important unknowns is why some people’s immune systems are up to the task of clearing out the virus while others are sluggish or overreact, leading to death. Just as vexing:
- How do we know for sure if a person is immune to Covid-19 after infection?
- What percentage of the US population will be immune after this first wave of infections is over?
- Will immunity last over time, or will it fade?
- Can a vaccine provide immunity and stop the pandemic?