CountChocula wrote:
This is an interesting point that I have thought about quite a bit myself. North Dakota (and some other states) saw huge increases this fall in the number of cases, followed by huge increases in the number of deaths. But for the past few weeks ND has seen a big decline in cases (and deaths, to an extent). What might be the cause? The introduction of a mask mandate? A change in people's behavior? Fewer people getting tested?
I'm not advocating for any particular viewpoint; just think it's worth discussing.
ND's test positivity numbers (# positive / # new tests), were, by a wide margin the highest in the country (close to 80% at one point) so we can discount widespread testing for the increase. At present, they're still at about 50% so they don't appear to be doing much asymptomatic testing and can't be doing contact tracing with those kinds of numbers.
I think the only plausible reasons for the decline is a change in behavior, whether by mandate or widespread personal choice or some level of (regional?) herd immunity. The rational for the former is that North Dakota is a pretty sparsely populated state so even a minimal effort to socially distance could have a large effect. The case for herd immunity is that 15% of the state population has had a documented positive test and the state apparently wasn't doing much asymptomatic testing, thus the infection rate is certainly higher than the documented case rate and plausibly several times higher.