Japan COVID-19 Stats Update 5: Things have continued to improve these last two weeks. Surely plenty of speculation as to why in the months ahead; and with the state of emergency lifting in many places, a reversal of current trends is likely. But lets see what these trends are:

First, while newly tested individuals dropped off during Golden Week, this week saw the highest number of newly tested individuals yet:

Nevertheless, confirmed positive COVID-19 have cratered to a very low level, irrespective of the ups and downs of testing numbers

So if we compare total tests and total cases side by side, the shapes of the curves are precisely what we want to see.

For comparison, here is how the rolling 7-Day means for daily tests and confirmed cases have tracked over time. (7-Day rolling mean ideal as day of week produces quite a bit of variability it seems)

Following on from that, the most encouraging sign is a major drop in the 7-day PCR detection rate (percentage of tested individuals testing positive). WHO standards are to keep testing vigorously until rates are under 10%.

At its peak of testing, the ROK was getting around 3%. Getting things down to 1.25% among mostly symptomatics is surely some good news.

Discharges as a way to relieve the burden on the health system continue to accelerate. This week saw a remarkable 3401 released from hospital or the need for ongoing medical care/surveillance

Also, last week was a milestone of sorts in that the number of discharged cases exceeded new confirmed cases.

Or if you prefer, the data as a 7-day rolling mean of daily cases, showing that May 3 was a key date.

These two trends have resulted in a dramatic week-on-week drop in active cases.

Also a similarly pleasant-looking curve for serious active cases. This tends to be a lagging indicator of the above, so hopefully there might be at least one more week baked-in of decreasing patients in ICUs/on ventilation support.

Promisingly, deceased cases dropped under 100 for the first time since the week ending April 15.

Which resulted in an undershooting of even the expected numbers suggested by the earlier relationship between confirmed cases and deceased cases (LR, Y-2t).

So with the partial relaxation of the state of emergency being announced in some places, the acceleration over the last week of positive trends may be lost. Still, Tokyo and others will remain under cautious surveillance.

Furthermore, the last two spikes in cases due to community spread purportedly grew out of infected persons entering Japan (both Japanese & non) from China, & then later Europe/US. Since entry restrictions won't be relaxed as Japan opens up, we'll get to test that assertion.