The coronavirus seeks only to replicate. We seek to halt that replication. Unlike the virus, humans make choices. This pandemic will pass into history. But the way in which it passes will shape the world it leaves behind. It is the first such pandemic for a century. And it comes to a world that — unlike in 1918, when the Spanish flu hit — has been at peace and enjoys unprecedented wealth. We should be able to manage it well. If we do not do so, this will be a turning point for the worse.

Making the right decisions requires that we understand the options and their moral implications. We now confront two fundamental sets of choices: within our countries and across borders.

In high-income countries, the biggest choice is how aggressively to halt transmission of the virus. But we also need to decide who will bear the costs of that choice and how.