Hi Everyone,
Not much change from last time in trends.
US Cases
· The number of new reported cases in the US outside of NY continues to decline slowly (Fig. 1; P = 0.0074 after day 50).
· The number of new tests in the US outside of NY continues to increase linearly (Fig. 2). As of yesterday there have been approximately 20 million tests performed in the US.
· The number of new cases per test also continues to decrease (Fig. 3), albeit slowly (P = 0.0113 after day 71), suggesting that the actual number of new cases per day is also slowly declining.
· The cumulative number of new cases per test still fits a modified logistic well (Fig. 4)
· Extrapolation from this fit suggests that most of the infections associated with the first wave will have occurred by about day 100 (8 June—yesterday). Specifically, for the US outside of NY, on days 99, 129, and 169 (7 June, 7July, and 16 Aug, respectively—these dates are 1-2 days later than projected last time), 95%, 99%, and 99.9% of the total infections during the first wave of the virus will have occurred. On these dates, the minimum number of infections yet to come are 85,753, 17,954, and 2,152. On days 129 and 169, the expected minimum number of new cases will be 972 and 118.
US Deaths
· US deaths outside of NY continue their linear decline (Fig. 6)
· Projecting this trend, the day at which 0 new deaths is achieved will be day 137 (15 July), though given the error of estimation, it could be as late as day 204 (20 September). The latter date is quite a bit earlier than the November date projected previously, which is due to the additional data points we now have. Certainly an excellent trend.
Fig 1
Fig 2
Fig 3 Fig 4
Fig 5 Fig 6
NC Cases
· We’re seeing a return of the virus to NC. The number of new reported cases per day continues to increase linearly in North Carolina (Fig. 7).
· Ominously, the number of new cases per test seems also be increasing over the past three weeks (Fig. 8; linear trend after day 73, P = 0.0009). We’ll need to keep an eye on this to see if the actual number of new cases continues to rise.
NC Deaths
· As might be expected from the small sample size, the number of new deaths per day in NC is very volatile (Fig. 9). We’ve seen some large spikes in the last 10 days, but the trend at this point is not significantly different from flat. That is not good news, though, since there is no sign of it declining. If the number of new cases is actually climbing, we will expect the number of new deaths also to begin rising in the next week or two.
Fig 7
Fig 8
Fig 9
Conclusions
Things are looking good for the US as a whole. The number of new cases per test continues to decline, with an indication that we have already passed the point at which 95% of the new cases have occurred. Similarly, new deaths are declining steadily, with the 0-death day projected to be in just a little over a month, assuming the current trend continues. Of course, that is a big assumption.
As was true last time, however, North Carolina seems to be going against this trend. There as actually been an apparent increase in new cases per test over the last three weeks, which portends a second wave of infections. New deaths also show no sign of decreasing. Both of these trends suggest that NC will be suffering from the virus substantially longer than the US as a whole. So be careful, and consider continuing your social distancing as much as possible.
Stay safe!
