"The worst thing now would be for...the vaccine programme to breed any kind of complacency"
I really hope this isn't the assumption the government are operating under because it seems obvious that as the vaccines roll out to friends and family, people will relax. Many people are agreeing to do things they consider inhuman because we're in the most extreme situation, once people feel it is no longer so extreme, they won't be as vigilant.
And once some people in the community start to relax, particularly those you know, you'll start relaxing too. Once the people "at risk" in your community are vaccinated, then you'll be able to rationalise the wider community risks away, and feel more comfortable taking your own personal risks. Even when those rationalisations are based on miscalculations of the risk.
Wouldn't be surprised to see a big spike in hospitalisations among the 45-64 year old age group towards the end of Feb.
Once their parents and elderly family and friends are safe, I think a lot of people will start socialising relatively normally. That age group are still about 50% less likely to be infected than younger adults because they adhere more strongly to the restrictions, but they're 3-4x as likely to be hospitalised. If 3x as many people aged 45-64 got infected as do currently, which doesn't seem a huge leap given the sheltered lives so many are living currently, it would make up for all of the 65+s no longer in hospital.
The estimates are based on the hospitalisation rates from
here, which suggest in the week after Christmas there were around 200 kids aged 0-14 newly hospitalised with covid, 2,000 15-44 year olds, 5,000 45-64 year olds, 3,500 65-74 year olds, 4,500 75-84 year olds, and 4,000 85+. All of which totals up to just over 19,000 cases, which matches the total for England from
here, so probably underestimates the UK total for each age group by ~ 15%.