[quote Sunshinegirl82]@BigChocFrenzy
You have misinterpreted my post.
What I mean is that the idea that if a vaccine is a long way off we will have to "rinse and repeat" with a full on epidemic every few years doesn't seem likely to me, even if immunity is reasonably short lived. There would be a reasonable amount of immunity in the community most of the time because people are not infected simultaneously and don't lose immunity simultaneously.
The situation is the same if a vaccine only provides relatively short lived immunity. [/quote]
....
By rinse and repeat I don't mean exactly the same each year, just that it would likely take years, not just 1-2:
There would be year 1 with up to 90% able to be infected, but most would not be
then each year a reduced number, as some gain immunity and some lose it - immunity for only 1-2 years means the process takes longer than for viruses where immunity is ~lifelong
Babies being born would keep bringing in new people without immunity too
"Overshoot" would mean a 20-25% higher level required than by vaccination
From studies of hard hit areas, that could be 70% in densely populated countries
Adam Kucharski explains the longer process, with studies:
threadreaderapp.com/thread/1305436391707467776.html