Think the term herd immunity is being massively misused. I prefer to look at it as Herd resistance and diminishing returns and so far it looks like the R rate keeps at 1.05% until it hits the peak (which lasts around 2 weeks) and then you start seeing the charts go below R=1 and that around when the official cases hit 1% of the population in area
In other words you see the total cases double every 14 days until 1% of the population gets infected, then after that it goes in reverse.
So the cases will then double each 28 days, then 56 days, then every 112 days. That's when the R drops 0.95, 0.90
So hitting 70% for "herd immunity" won't really be possible, not within a year or two timeframe, more like 10 years.