The serial interval of the virus is so fast that there's no way the T-cells and B-cells can keep up. Some sort of nasal vaccine could reduce infection for a few months but as far as I can tell it's impossible to make a long lasting (years) coronavirus vaccine that can prevent infection. Serial interval is too fast, antibodies wane too fast, your immune system is too slow. I could see a gene therapy/retrovirus thing that hijacks some cells permanently to produce antigens (or make it smarter and somewhat regulating like an HIV infection, if HIV is forever this could be too) so it's like getting vaccinated every minute of every hour of every day, forever. Alternatively, you could produce genetically engineered B-cells in the lab and inject them into people ('s bone marrow?) to constantly produce a very high dose cocktail of broadly neutralizing antibodies. Completely infeasible, too expensive, won't scale. Might work. None of these ideas would be approved for the general public in at least 25 years.
