It's a scientific question as to whether a specific limit on freedom (of movement, of contact, etc.) is effective.
But it's a general approximation that greater freedoms mean higher mortality rates during lethal pandemics. And vice versus.
What level of mortality we're prepared to accept, and what level of limitations on freedom, is a political question in a democracy.
That's the eternal question. Not just for disease control, but for everything.
> What are the criteria for determining necessity?
In a democracy, ultimately: elections.
It's a scientific question as to whether a specific limit on freedom (of movement, of contact, etc.) is effective.
But it's a general approximation that greater freedoms mean higher mortality rates during lethal pandemics. And vice versus.
What level of mortality we're prepared to accept, and what level of limitations on freedom, is a political question in a democracy.