And the most important unknown about our response is whether governments can retain the trust of enough people to implement effective control measures.

It's shaping up to be a hard winter.

Although there are important roles for better ventilation and effective testing programs, success confronting Covid will, on one hand, take increased vaccination and indoor masking, including through mandates, and on the other hand, individual and societal decisions on balancing individual and collective risks and benefits.

First, vaccinate, vaccinate, vaccinate.

Rapidly expanding production of highly effective mRNA vaccines is our best hope of preventing more dangerous variants from causing another pandemic wave.

Mask mandates need to be implemented, enforced, and adherence monitored to build a collective sense of responsibility and achievement at high levels of mask wearing.

Fix the market so anyone can buy an effective mask at a reasonable price, and give away masks, including N95s, to those who need them.

Vaccination and indoor mask mandates are required, both ethically and for disease control.

Ratcheting protections up and down based on how much Covid is spreading -- how hard it's raining Covid outside -- can help, but which gatherings to restrict, whether to go to restaurants and bars, and how to balance economic activity with protecting public health can have different right answers for different people, at different times and in different places.

Pandemics -- including pandemics caused by new SARS-CoV-2 variants -- are not inevitable.