Interesting discussion with a couple physicians today and the issue of herd immunity. It was asked "What would it look like if we pulled a lever and 90% of the population was vaccinated?" This brings up some questions that, while unanswered to a degree, have things to consider when answering the question...

Would high level of vaccinated eliminate Covid? My answer is no. Virus will become endemic and eventually all adults will have been exposed or vaccinated, then as children are exposed at early age, the deadly outcomes will be rare and a level of immunity (although perhaps not detectable by antibody tests) will persist and protect against the worst outcomes such as death. Re-exposures will be met with illness but not severe illness in those that have immunity. We know vaccine is "leaky" and that vaccinated and prior infected can become infected despite prior antibodies thus complete elimination of Covid (barring a new non-leaky vaccine) is extremely unlikely. With high level of vaccination, I still expect outbreaks and transmission: https://www.forbes.com/sites/roberthart/2021/05/11/covid-surges-in-4-of-5-worlds-most-vaccinated-countries-heres-why-the-us-should-worry/?sh=777eee56d677

Would it decrease death rates? Very simply, yes. The more vaccinated, the less will have poor outcomes including death.

Would there be any potential unintended side effects of highly vaccinated population? Perhaps. Exposure of virus to vaccinated or otherwise immune may select out (favor) any viral mutations that are poorly recognized by the established immunity of the current vaccine. https://www.npr.org/2021/02/09/965703047/vaccines-could-drive-the-evolution-of-more-covid-19-mutants