Inoculation rates are seldom going to be 100% as there's very good reasons for some people to not get a vaccine (e.g. immune-compromised individuals), so there'

Inoculation rates are seldom going to be 100% as there's very good reasons for some people to not get a vaccine (e.g. immune-compromised individuals), so there's always going to be some level of the virus circulating and that's assuming that the vaccine is 100% effective which seems unlikely. Of course, the vaccination levels are far less than 100%, but typically enough to prevent the virus spreading too far - the problem now seems to be that vaccination rates in some areas are dropping below the level that prevents it spreading.