Liberals get it first so we can make sure it doesn't have any long term side effects.
They'll be ok with it because they love big government, so government can force it on them and we'll sit back and see if its safe
After that though, probably start with the sick people with a high chance of dying, then the elderly, medical staff and the people who will most likely encounter the elderly.
Almost every infected person isn't even aware they have it, so I think most age groups can do without until later. Elderly people on the other hand have a much higher risk of dying