Related to boosters, Pfizer released phase 3 trial data from boosters involving about 10K people from their original trials. They randomized the participants and gave half a 3rd dose and half a placebo. The efficacy for the booster came it at 95.6% after an average followup of about 2.5 months.
The important caveat with that efficacy number is that it's 95.6% vs. the group with 2 doses, not an unvaccinated group. So the protection vs. the unvaccinated is even higher (probably 97-99% depending on the level of protection the 2 dose + placebo had).
https://www.pfizer.com/news/press-re...l-data-showing
Presumably that protection will wane too, but it does bode well for being able to protect vulnerable people from getting infected at all if they take boosters.