Shortening is a likely outcome. But in theory it's even possible that the immune response prepared by the vaccine only prevents virus spread to organs where we

Shortening is a likely outcome. But in theory it's even possible that the immune response prepared by the vaccine only prevents virus spread to organs where we notice symptoms but does not clear out those places that the virus colonizes during the pre-symptomatic infectivity phase that seems to be the super-power of this particular virus. And that this success prevents another immune response that would otherwise clear out those spreading springboards. Of course this perfect storm of what could be called "vaccine enhanced infectivity" is an extremely unlikely scenario, but at least weak forms of it that cause longer infectivity, but not much longer or even permanent infectivity could remain undetected for years. The reason for all this uncertainty is simple: testing for infectivity doesn't scale, definitely not enough to continuously observe test groups large enough to experience cases. But Ithink there is hope: chances are someone is designing a study that recruits a number vaccinated that live together with someone unvaccinated. Then in case their unvaccinated peer falls ill you can observe the vaccinated one, that should be well in the test scaling envelope. We know the attack rate in unvaccinated households and can compare.