There is one New Zealand blog I follow where I disagree with almost everything that is posted. I follow it to remind myself that there are locals who have a radically different world view from mine. My opinions of their postings range from ignorant claptrap to idiotic nonsense, although very occasionally (and I emphasis very occasionally) I find a post that I can almost agree with.
My impression of those who comment on the blog is that most are anti-vaxxers, covid deniers, conspiracy theorists of various types, and mostly right wing (by NZ standards). In a post today, the writer lamented the fact that they had to cancel a restaurant booking due to the yesterday’s lockdown notice. Let me quote part of the article:
Call me simple and definitely cynical if you like but I fail to see any value to any of our group, the restaurant and its staff and the New Zealand Covid extinction by locking down anywhere south of about Hamilton and locking down the South Island is surely over kill.
Ok, I call you simple. It’s not about you.
In my view the blogger has a ludicrously overly simplistic understanding of how covid is transmitted. We know: the Delta variant is highly contagious – even a fleeting contact such as one person walking past another in a park; the case identified yesterday had been infectious in the community for many days and had visited at least 25 locations over that period, some hundreds of kilometres apart; the source of the infection is unknown; Kiwis are a highly mobile lot and I guess there’s been many tens of thousands of us who have travelled in and out of the Auckland and Coromandel regions from all around NZ over the past week. I can guarantee there have been hundreds, if not thousands of individuals who will have travelled between the poster’s home town and Auckland or Coromandel during the period in question.
While it’s highly unlikely that the writer or their dining friends will come into contact with an infectious person, the odds are very high that someone in their hometown who will be either a primary or secondary contact of the yesterday’s case or one of the six related cases identified so far today. Likewise, there’s probably thousands who have travelled between Auckland and the South Island in the week prior to lockdown. Sure, it’s highly unlikely that a specific person (the blogger in this case) will be a person of interest, but you can bet your bottom dollar that there’s at least one person in his hometown and the South Island who will be.
I think the blogger fails to understand the exponential rate of transmission of the Delta variant. It has an R0 factor of between 5 and 8. This means that a single person, on average, will infect between 5 and 8 other persons. In a best case scenario, one person will infect 5 who will infect 25 who will infect 125 who will infect 625 who will infect 3125. that’s a total of 3906 people in just five iterations. In a worse case scenario, and ignoring any superspreading event, the same number of iterations will result in a total of 37,449 infections.
Two independent modelling exercises indicate that with the immediate level 4 lockdown as of last night, the single reported case is likely to rise to somewhere between 50 and 130 before it’s squashed. It’s already at seven, and as yet we do not know the source of the current outbreak, the modelling may greatly underestimate what the final figure will be.
At the start of the pandemic, our government had intended to follow the same course that most other nations did – flatten the curve to prevent the outbreak from overwhelming the health system. However even the most optimistic modelling projections showed that the NZ health system would be totally overwhelmed in very short time. Hence the change to an elimination strategy shortly after covid arrived here. Given that this is the first lockdown we’ve had outside of Auckland apart from the initial 6-week lockdown in March last year, I am firmly convinced that it has been the correct path to follow.
We do know that this particular outbreak is related to the New South Wales, Australia strain of the Delta variant, so now there is a scramble to trace exactly how it arrived in this country. Genome sequencing can estimate how many intermediaries there have been between a known case and a newly discovered case, and due to the strictly controlled nature of entry into Aotearoa New Zealand, I think that there’s a good chance of tracking its path from NSW to NZ.
Update: As of 7 pm, today, the total number of cases has risen to ten. One case is a teacher at a high school, another is a fully vaccinated nurse in a public hospital, and another is a student who attended a lecture yesterday along with 80 others. These three instances are possible super spreading events that could seriously skew modelling estimates. One case is now known to have a connection with the border. Similar to the situation elsewhere most of the delta infections are in younger adults – here, mostly in their 20s.