Since somebody asked about population of under 5s (on the theory that Pfizer will likely be approved for 5-11s), I checked Stats NZ, and as at 30 June 2021, they estimate that age group as 305,190 out of 5,106,300. The 5-11s are estimated as 462,850, so nearly 10% of the total population.
From that, currently around 85% are eligible to be vaccinated, and if we get 80% of that eligible group vaccinated, that still leaves 1.6 million unvaccinated, plus Delta does still affect the vaccinated, but hospitalisation rates are tiny (LA data suggests 1 in 100,000, which is neglible in NZ's population compared to numbers below).
Current estimates are that Delta spreads at R0=6, but even if we drop that to R Eff =2 to account for vaccinations and level 2 measures, that would infect most of the country in around 20-22 cycles (so 9-10 months). R Eff and spread is a bit of a red herring though - if R Eff is >1, everyone unvaccinated will get it eventually, and if R Eff is closer to 2 or higher, that eventually will be pretty quick other than perhaps in really rural areas.
If I'm lazy and run with 5% hospitalisation and 0.5% death rates in that whole 1.6 million unvaccinated, that would be 81,000 hospitalisations and 8,100 deaths, large numbers of whom would be under 12s. Note that I haven't adjusted for age or any other risk factors, so obviously as the model gets more sophisticated, the hospitalisation and death rates would change.
If vaccination rate of those 12 and over was 90%, that would decrease hospitalisation and deaths to around 61,000 and 6,100 respectively. 75% of same would be hospitalisation and deaths of 92,630 and 9,263 respectively.
Halve the hospitalisation and death rates, and/or spread those over two years, and it would still be a lot of hospitalisation and death, and they wouldn't necessarily be spread evenly - more likely to come in waves/clumps.
That's obviously an extremely simplified model, and a better model would adjust some groups upwards due to age and other comorbidities while adjusting the children down. Public health measures/restrictions would also be modelled in a range of scenarios, and so on. However, I think 7,000 is plausible in a low vaccination, low restriction environment. Obviously adjust either vaccinations and/or restrictions upwards, and number of hospitalisations and deaths will fall rapidly and spread out over time as well.
