I have just placed a comment on deaths, lifting lock down, and the effect of vaccinations on summer 2021 but am putting the vaccines bit here as well.
Vaccination of the first tranche by 15 Feb (Groups 1-4 - say 12M - takes into account 20% refusals (variety of reasons)) will mean that, by 26 Feb (15 Feb + 11 days) 88% of people who unvaccinated would catch COVID-19, then develop serious illness (some then dying), will NOT (even) develop serious illness. Win! (for those vaccinated, and for the NHS both in terms of numbers of patients and staff illness and self-isolation absence, and probably for all those (1.2M, say) that the 12M don't transmit the infection to - but we haven't got evidence for that vaccine effect.)
Provided vaccine supplies remain sufficient (to allow 2.5M doses delivered per week), we should have
vaccinated all the Groups (1-9 - #27M (NB 33M less 20%)) laid out by JCVI
by mid Apr (all over 50s and and - see JCVI list). NB takes into account that second doses will take about half the delivery from 14 Mar onwards.
The adult (over 16) population of UK is 67M -
ONS, (54M adults). At that vaccination rate (2.5M per week, half is second dose) we might hope to reach
herd immunity at 80% (of adult population so 43M, opinions vary on the percentage required which depends on several factors)
by early July. (NB I am not counting in any of the unvaccinated million + who've had COVID-19 and retained sufficient antibodies to get to 80%.) The summer months will also help (the average number of excess deaths mid-Jun to mid-Sep 2020 was very low). And in July and August the remainder (10M) of the adult population (O/16) and vulnerable under 16s (clinical judgement at this stage) can be vaccinated. If the decision is taken to vaccinate under 16s, this might neatly be achieved by doing so on in the first week of term.
Summer holiday in UK everyone? Let's hope for good weather and tailwinds.