Commentary: The key to unlocking the mysteries of COVID-19 is understanding immunity
Among the many medical puzzles about COVID-19 that continue to confound experts: Why does one spouse contract COVID-19 while in many cases the other does not? Why does the African continent have far fewer COVID-19 cases and deaths per capita than the other continents? Why does Singapore have more COVID-19 cases per capita than the U.S. but less than one-tenth the per capita death rate? What protects better from future COVID-19 infection, previous infection or vaccination?
Some of the
