The last four World Health Organization Coronavirus disease situation reports, 63-66, show an almost flat number of new tested-and-reported COVID-19 cases worldwide each day:
- 46,484 (report 67; March 27; bold face because added as an update)
- 62,514 (report 68; March 28)
- 63,159 (report 69; March 29)
- 58,411 (report 70; March 30)
- 57,610 (report 71; March 31)
- 72,736 (report 72; April 1)
- 72,839 (report 73; April 2)
- 75,853 (report 74; April 3)
- 79,332 (report 75; April 4)
- 82,061 (report 76; April 5)
- 77,200 (report 77; April 6)
- 68,766 (report 78; April 7)
- 73,639 (report 79; April 8)
- 82,837 (report 80; April 9)
Original text, before the data points in bold were added: Almost, but not quite flat, right? After four days it grew from around 40,000 to around 50,000. But consider these data against the background of a rapidly ramping up testing infrastructure. More people are being tested, not just celebrities and political elites with mild symptoms and peasant hospital inpatients. If dramatically more people are being tested every few days (and therefore fewer mild cases never get noticed/recorded as COVID-19), don’t the above data suggest that the actual number of new cases (humans actually infected as opposed to the proper subset of humans tested and reported as infected) is going down?
- March 25 report: 679 new cases
- March 26 report: 579 new cases
- March 27 report: 823 new cases (5,750 tests)
- March 28 report: 1,107 new cases (5,678 tests)
- March 29 report: 698 new cases (4,017 tests)
- March 30 report: 797 new cases (3,727 tests)
- March 31 report: 868 new cases (4,142 tests)
- April 1 report: 1,118 cases (4,803 tests)
- April 2 report: 1,228 cases (4,870 tests)
- April 3 report: 1,436 cases (6,354 tests)
- April 4 report: 1,334 cases (5,838 tests)
- April 5 report: 764 cases (3,137 tests, a Sunday)
- April 6 report: 1,337 cases (4,492 tests, lab staff back to work on a Monday?)
- April 7 report: 1,365 cases (4,915 tests)
- April 8 report: 1,588 new cases (6,167 tests)
- April 9 report: 2,151 new cases (7,447 tests)
3/27 analysis: Not an obvious exponential growth process and, even if it were, patients aren’t generally tested until admitted to a hospital (i.e., current growth in cases reflects a growth in infections that happened 1-2 weeks ago)
[Update, evening 3/27, text message from friend: “I asked [physician wife] how her nurse friend is doing at the hospital. She said she has not worked in a week because the ER is so dead she can’t get hours. The hospitals are empty.”]
3/28 analysis: The Massachusetts data are worrisome. The number of reported tests stayed constant from March 27-28, but the percentage of positives grew. We have no information about when samples were taken, however, so this growth could have occurred several days earlier. (Test results show up in this report on the day that the tests are completed.) The WHO data suggest that the answer to the question posted in the headline is “no” (though it is tough to say given that the WHO situation report does not say how many tests are being performed worldwide).
3/29 analysis: Massachusetts testing actually fell. Only 17 percent of tests were positive, about the same as the average of the two previous days. Linear growth is a better fit than exponential growth. The WHO data suggest weak exponential growth.
3/30 analysis: Massachusetts testing fell again, but 21 percent tested positive. Suggests that doctors are now better at figuring out who needs to be hospitalized (since it is hospitalization that leads to being tested). WHO data show a slightly reduced number of both cases and deaths.
3/31 comment: Where’s the exponential growth?
4/1 comment: Okay, maybe we do have (slow) exponential growth in both worldwide and Massachusetts cases.
4/2 comment: The world is doing better than Massachusetts, but if Farr’s law is in operation, it is tough to guess the top of the bell curve.
4/3 comment: Sweden (open) has 2X the population of Denmark (locked down), so the 519:279 ratio of new cases works out to roughly the same as the population. The ratio of deaths (43:19) is also roughly the same as population ratio. So it looks as though the Swedish epidemiologist’s prediction that government policy would have a minimal effect is proving correct. For the world overall, it has been 11 days and still the number of new cases has not doubled. WHO is still not publishing data regarding how many tests are being performed, so there is no way to know if this slow doubling corresponds to a 4X increase in testing and a falling number of actual new infections or a steady rate of testing and a doubling-every-two-weeks rate of actual new infections. Massachusetts data suggest doubling every 8-9 days. They also confirm the wisdom of the New Yorkers who fled via Gulfstream to their Nantucket mansions: only 9 cases on the island.
4/4 comment: Sweden continues to have roughly the same number of new cases, per capita, as Norway and Denmark, and Swedish hospital/ICU capacity remains sufficient (and public). It seems to be essentially impossible to die from COVID-19 in Norway. Do they have a better treatment that they’re not sharing? Or do they record the death of someone with underlying conditions differently? Or are they keeping people on ventilators beyond the point at which the Swedes would have given up hope?
4/5 comment: Sweden has 365 new cases; Denmark has 320. Keeping in mind that Sweden has 2X the population, this suggests that the Danish “lockdown” is not “making a difference” as rich Americans like to say. Massachusetts is back to the same number of new cases as 9 days ago. Farr’s law, but with an extremely poor fit to a Gaussian?
Monday, 4/6 comment: Sweden has 387 new cases; Denmark has 292. I.e., Sweden continues to have a lower per-capita new-case rate despite the lack of a lockdown. Sweden even has a lower per-capita death rate, 28:18. Spain and the UK are contributing hugely to the world total of new cases, each with roughly 6,000. Massachusetts numbers are back where we’d expect them to be, perhaps due to reduced lab activity on Sunday.
4/7 comment: Sweden has 376 new cases; Denmark has 312. The per capita new death ratio is no longer favorable to Sweden, however, at 4.75X (small sample, however; Denmark had only 8 deaths). Globally, COVID-19 has killed more than 72,000 people, i.e., about the same as the number of Americans killed each year by taxpayer-funded (via Medicaid) opioid addiction and overdose. But the new case count seems to be declining in accordance with Farr’s law. The Massachusetts numbers are worrisome. New cases are stubbornly high and 356 people have died so far (roughly the same, per capita as in Sweden; i.e., a poor argument for our state’s school closure and other shutdown efforts).
4/8 comment: Sweden has 487 new cases; Denmark has 390 (i.e., more per capita in the locked-down country). Worldwide new cases are still on a plateau. Massachusetts cases continue to grow, consistent with a doom-and-gloom forecast from University of Washington that Massachusetts will end up worse than New York, adjusted for population. Fully 2.6 percent of people in Massachusetts with confirmed cases are already dead, suggesting that we are not better at caring for patients than were the doctors working in Wuhan (death rate roughly 1.4 percent). As in China, though, our data are skewed by limited testing.
4/9 comment: Sweden is at 726 new cases; Denmark 331 (comparable when adjusted for population size). Worldwide new cases continue on a plateau. Massachusetts in shutdown seems to delivering the exponential growth that the media was hoping to see from wide open Sweden.