One clarification - between 0.01% and 0.29% (actually 0.54% now) of fully vaccinated people are affected by breakthrough infection, while 88% effective means in

One clarification - between 0.01% and 0.29% (actually 0.54% now) of fully vaccinated people are affected by breakthrough infection, while 88% effective means in a situation where an unvaccinated person would become infected, the vaccinated person would have an 88% chance of not being infected. So the difference between the two is exposure, which is a function of prevalence.