OP I don't think I understand how the mechanism for what you're describing would work.
So: lets say before there are vaccines, x% of people who are exposed to covid will become infected, y% will need hospitalisation and z% will die.
With vaccine, X-50% who are double jabbed will become infected, y-50% will need hospitalisation and z-50% will die. That isn't breaking the connection, its reducing the effect. Also, the 'delay' mechanism would mean you don't believe there's any effect to the x% who are infected, or the y% who are hospitalised or the z% who die, just that the time between x being infected and z dying is somehow longer? I don't really understand how that would work?
The '-50%' figure is just a placeholder, but vaccines work by giving you antibodies. In some people, with some infections, this will mean you won't be infected in the first place. With some others, you'll still be infected but the amount of infection in your system will be reduced, possibly to a level that won't allow you to transmit it to others. We're not 100% sure on how these vaccines work but it seems like its a mix of all three depending on the vaccine given and the recipient.
The issue with the figures at the moment are: 1) the people who are vaccinated are disproportionate across the population: the y% hospitalised and z% who die were never random figures, they were affected by age and health, which also affects who is fully vaccinated at the moment. So you'd expect, in a massive upsurge of cases, that even if the vaccine worked as I suggested it wouldn't have any effect on younger people who were already going to have a lower % of people hospitalised and dead in their cohort.
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We don't know exactly how variants play in.
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The relaxation of restrictions mean we're not comparing 'population pre-vaccine under lockdown' to 'population post-vaccine under lockdown' so obviously there will be a change in the figures as more people will be exposed.
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Some people's bodies do not react to the vaccine, either because they're immune-compromised or for other reasons.
I am really keen to understand the answer to: how many fully vaccinated people will be sick but not seriously effected, if the reduction in this applies evenly across risk groups or not, how foetuses are affected if mothers are vaccinated and the mother still gets ill but only mildly, and how boosters will effect variants. I don't think we have data to be sure about these things. But I feel pretty confident the data is there to suggest the vaccines aren't just producing a time lag in people who go onto contract the virus having been vaccinated.