Good point! Although, we really haven't stopped the spread of the stronger one, bending the curve is just slowing it down. Maybe the milder one could be spread faster if it were intentional?

The same way we spread polio vaccination: vaccinated personnel can safely visit people everywhere (in this case, they might have to take a few more precautions than with polio)

You could also set up places where people can go to be vaccinated. Those could become hearths of infection, but precautions like those already in place for shopping would minimize that risk.

Depending on the ease of administration, you could even just mail everybody a dose and let them self-apply.