Everyone should be adhering to using PPE, not touc

Everyone should be adhering to using PPE, not touching orifices with fingers if possible, distancing, avoiding enclosed areas / recirculated air, not utilizing public restrooms, transportation, etc....

even if they've had a vaccine. First dose, second dose, whatever.

There's no clear data on what 'vaccination' really means.. it's likely that, at minimum, it'll lessen disease course/severity. It doesn't appear to prevent infection. It's unclear wether it will lessen spread. It's unfortunately likely that not enough people will receive it an the virus will still find hosts to evade eradication and eventually develop immunity.

Will someone infected with a new variant for a second time have a lesser, same, or worse reaction than the first time? How about someone who was vaccinated? After first exposure, does it become effectively a heavy cold, or is it a hyperimmune reaction, like Dengue?

Isolation will only work to the extent everyone does it. I would, to protect those I come in contact with, and avoid unnecessary exposure, but I see risk as a constant, two, three, however many weeks out.