the reasons why countries that are supposedly fully vaccinated are heaving breakouts is because some people are not fully vaccinated.
I'll provide the argumentation in the links below.
Have a nice day and do vaccinate so your country can return to opening venues again. If not for your fellow man, do it for yourself.

https://www.polygraph.info/a/fact-check-gibraltar-vaccination-covid-surge/31589031.html
https://www.lung.org/blog/understanding-covid-herd-immunity
https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/herd-immunity-and-coronavirus/art-20486808