COVID-19 New Case Rate vs. Proportion Infected

COVID-19 semilog phase diagram data visualisation by John Chew <poslfit@gmail.com>

To suggest improvements or report errors, please email poslfit@gmail.com.

Data compiled from a variety of online sources as identified in comments in Reported Cases headings.

Commentary

I’ve been posting commentary on Facebook about the “days to 1%” line in my Google Sheet linked above. Here is a sample of what I’ve written.

Boilerplate explanation paragraph: The number in question given with each country is my own way of boiling down your region or country's growth/doubling rate and number of people infected with COVID-19 into one number. It represents the number of days you have left at your current rate of infection (averaged over the last four days) before you reach 1%. It's not a forecast (your rate of change is likely to change before then, when public health authorities take positive or negative action), just one simple number that tells you how you're doing compared to others. I could have picked a bigger percentage than 1%, but you can't go too far before the exponential growth bends back down logistically, and it seemed as easy a place as any; most people can visualize the idea of 1 in 100.

2020-03-29

Today's numbers: New York State (7), Turkey (14), Louisiana State (15), Spain (15), U.S.A. (16), U.K. (20), France (24), Germany (24), Canada (26), Italy (27), Ontario (29), Norway (30), Toronto (31), Australia (33), Iran (36), Denmark (38), Mexico (39), South Africa (42), Brazil (44), Singapore (58), Malaysia (61), Indonesia (63), Thailand (65), India (67), Japan (71), Malta (89), South Korea (357), China (7615)

Compared to yesterday, here's how these regions are doing.

Much worse: Japan (again)

Same: Denmark, Mexico, Ontario

Slightly better: Australia, Brazil (again), China, France, Germany, Iran, Italy (again), New York, Norway, Spain (again), Turkey, U.K. (again), U.S. (again)

Much better: Canada, Louisiana, Malaysia, Malta, Singapore, South Africa (again), Thailand (again), Toronto

Spain and Italy both saw several hundred fewer new cases today than yesterday, so maybe they are reaching their inflection point. I hope so: they're still seeing several thousand newly diagnosed cases daily.

In Ontario, we learned last night after we had done our grocery shopping for our weekly Sunday fictive family dinner that that dinner was now banned because it had more than five people. We cooked the food separately, exchanged some dishes with each other halfway between our houses, and had our dinner conversation over FaceTime. Thanks to earlier measures, Toronto's numbers have come down sharply in the last few days, and I'm hoping the new restrictions help confirm that we are past the worst of it. Fingers crossed.

I'm worried about Japan, which has not quite managed to bring their epidemic under control. People are generally very careful about respiratory disease transmission there, as they are in most Asian countries. It sounds like they're finding though that there are situations like that community centre yesterday where just one infected person can set back their efforts tremendously, and I'm not sure how they're going to control that.

Stay safe.

2020-03-28

Today's numbers: New York State (7), Louisiana State (12), Spain (13), Turkey (14), U.S.A. (16), U.K. (20), France (22), Germany (22), Canada (23), Italy (26), Toronto (27), Norway (29), Ontario (30), Australia (32), South Africa (33), Iran (36), Denmark (39), Mexico (40), Brazil (44), Malta (46), Singapore (47), Malaysia (55), Thailand (62), Japan (95), China (7,615).

Compared to yesterday, here's how these regions are doing.

Much worse: Japan

Worse: France, Malaysia

The same: New York State, Singapore, Turkey

Better: Brazil, Canada, Denmark, Italy, Malta, Ontario (again), Spain, Toronto, U.K., U.S. (again)

Much better: Australia (again), China (again), Norway, South Africa, Thailand (again)

As I posted elsewhere, I suspect Italy and Spain are not doing better; it just looks like they are because they've reached their testing capacity, so until they can increase it, they will keep seeing the same number of new cases each day, which will be a smaller percentage of a larger infected population.

Both Toronto and Ontario saw 12% increases today. That's good in terms of recent numbers, but the government is aware that here too we are restricting testing to critical cases, and as of today additional restrictions came into place banning social gatherings of more than five people. We need to get our spread much closer to zero, and now's the time to do it.

Japan reported a huge uptick today. It was announced that almost half of the new cases came from one super-spreader who worked in a community centre with a large number of disabled people. That's going to be a difficult lesson for Japan to learn. We've had similar cases across Canada too, and I worry about my aunts who are in a local nursing home.

The past history was starting to look cluttered, especially if you look at all the regions in my visualization tool, so I've added buttons that let you look only at past, present or future data. I've also added the American state of Louisiana, which is apparently being hit hard.

2020-03-27

Today's numbers: New York State (8), Spain (13), Turkey (15), U.S.A. (16), U.K. (19), Canada (21), Germany (22), Norway (23), South Africa (23), France (24), Italy (26), Toronto (26), Australia (28), Ontario (30), Iran (38), Denmark (39), Brazil (43), Mexico (45), Singapore (48), Malta (55), Thailand (56), Malaysia (57), Japan (120), China (7,543),

Boilerplate explanation paragraph: The number in question is my own way of boiling down your region or country's growth/doubling rate and number of people infected with COVID-19 into one number. It represents the number of days you have left at your current rate of infection (averaged over the last four days) before you reach 1%. It's not a forecast (your rate of change is likely to change before then, when public health authorities take positive or negative action), just one simple number that tells you how you're doing compared to others. I could have picked a bigger percentage than 1%, but you can't go too far before the exponential growth bends back down logistically, and it seemed as easy a place as any; most people can visualize the idea of 1 in 100.

Compared to yesterday, here's how these regions are doing.

Much worse: Denmark (again), Mexico, Norway, Toronto, U.K. (again)

A little better: Brazil, France, Germany, Japan, New York State, Ontario, South Africa, Spain, U.S.A.

Much better: Australia, Canada, China, Iran, Italy, Malaysia, Malta, Singapore, Thailand (again)

I understand the issue in Toronto is still returning travellers being diagnosed, and officials have warned that our numbers could increase substantially for a few days. At the other end of the country, officials in British Columbia were guardedly optimistic, saying that social distancing seemed in general to reduce transmission rates by a factor of two, and that there was a reasonable chance that everyone who needs care will receive it.

Denmark's "much worse" is still starting at a fairly good baseline, so not too much to worry about. They're drifting up toward 10% daily from 5%. Norway had a somewhat worse day than usual, at 12% rather than their recent 9%. Not good trends, but much better than other places.

Mexico was down to 10% one day recently, but is now consistently back in the 20% daily range.

2020-03-26

New York State (7), Spain (13), U.S.A. (16), Canada (18), Germany (21), South Africa (21), France (22), U.K. (23), Australia (25), Italy (26), Ontario (29), Norway (33), Malta (36), Brazil (41), Toronto (41), Singapore (43), Iran (44), Denmark (46), Malaysia (46), Thailand (47), Mexico (50), Japan (120), China (6,805),

Boilerplate explanation paragraph: The number in question is my own way of boiling down your region or country's growth/doubling rate and number of people infected with COVID-19 into one number. It represents the number of days you have left at your current rate of infection (averaged over the last four days) before you reach 1%. It's not a forecast (your rate of change is likely to change before then, when public health authorities take positive or negative action), just one simple number that tells you how you're doing compared to others. I could have picked a bigger percentage than 1%, but you can't go too far before the exponential growth bends back down logistically, and it seemed as easy a place as any; most people can visualize the idea of 1 in 100.

Compared to yesterday, here's how these regions are doing.

Much worse: Denmark, Germany, Iran (again), Japan, Malaysia, South Africa, U.K.

A little worse: China, France, Ontario, Singapore

The same: Canada, Spain

A little better: Australia, Italy, Mexico, New York State, Norway, U.S.

Much better: Brazil, Thailand (again), Toronto

Toronto saw a rise of only 6% today. 5% if you leave out returning travellers, who are becoming scarcer and contributing less to the new case numbers. That's the third time since the epidemic hit in full force that we've had new case numbers below 10%. It's not cause for complacency though; local public health staff are restricting access to testing, at least until the current test backlog is cleared. So some unknown part of the decline is reduced testing. The rule now is that if you have severe symptoms, or if you are in an at risk population and have good reason to think you're infected, you can get tested. Otherwise, just isolate and protect yourself from others and vice versa.

Canada's daily rate has dropped in the past four days 44%, 33%, 23%, 19%. Again, this might be due to undertesting, but let's hope not.

New York and the rest of the U.S. are gradually bringing their outbreak under control, with new daily reported cases down into the 20%s.

Australia has had two days in a row of increases down in the 10%s for the first time.

Italy, Japan and Denmark are now consistently below 10%. This is good news for Italy, whose overall numbers are so large that even small percentages affect large absolute numbers. It's less good news for Japan, which has shown difficulty in getting its rate down another order of magnitude to Chinese levels.

Stay safe, everybody.

2020-03-25

Today's numbers: New York State (6), Spain (14), U.S.A. (16), Canada (19), Australia (23), France (24), Germany (24), South Africa (25), Italy (26), Malta (26), U.K. (26), Norway (31), Thailand (32), Brazil (35), Ontario (36), Toronto (36), Singapore (47), Denmark (50), Iran (50), Malaysia (50), Mexico (50), Japan (164), China (7,997).

Compared to yesterday, here's how these regions are doing.

Much worse: Iran.

Worse: South Africa, Ontario, Singapore, Denmark.

A little worse: Canada, Malta, Japan, China.

Same: New York State, Germany, Norway.

A little better: Spain, U.S.A, Australia, France, U.K., Brazil, Toronto.

Better: Italy, Thailand, Malaysia, Mexico.

I know locally that Ontario has been seeing a steady influx of returning residents from out of the country, who as of this morning constituted half of the known new cases. Not much we can do about this, other than stay away from high concentrations of travellers, and ask the travellers to obey the requirements of the Quarantine Act.

Iran is much worse in the sense that they had 2200 or 9% new cases today when they had gotten down to below 5% daily a few days ago. News reports say the government is concerned that a second wave is building up, and that they are signalling that there will be tighter controls to come.

On the bright side, Italy has really turned things around, going from being the worst case in Europe to having the lowest new case rate outside of Asia. Their problem continues to be that even 7.5% of 70,000 people is a huge number of new cases.

Stay safe.

2020-03-24

Today's numbers: New York State (7), Spain (14), U.S.A. (15), Australia (21), Canada (21), Italy (22), France (24), Germany (25), U.K. (25), Malta (28), South Africa (28), Thailand (29), Norway (32), Brazil (33), Toronto (34), Ontario (40), Malaysia (46), Mexico (47), Singapore (50), Denmark (55), Iran (64), Japan (164), China (8,228).

Boilerplate explanation paragraph: The number in question is my own way of boiling down your region or country's growth/doubling rate and number of people infected with COVID-19 into one number. It represents the number of days you have left at your current rate of infection (averaged over the last four days) before you reach 1%. It's not a forecast (your rate of change is likely to change before then, when public health authorities take positive or negative action), just one simple number that tells you how you're doing compared to others. I could have picked a bigger percentage than 1%, but you can't go too far before the exponential growth bends back down logistically, and it seemed as easy a place as any; most people can visualize the idea of 1 in 100.

I added NYS today, because I'm worried about friends and family in New York. New York and Italy are the only regions on the list that have more than 1 person infected in a thousand, and New York is growing at 32% daily compared to Italy's 10%. That's the difference between growing tenfold in 8 days or 24.

I added the city of Toronto as well, because I live here. Apart from that, it's uninteresting: it has a higher density of infected people, but its growth rate is the same as the province of Ontario (15%), because it accounts for half the cases.

Some countries are doing a tiny bit worse: Spain, Canada, South Africa, Denmark, Iran, Japan. China has been having about 40 new cases out of 80,000 for the last few days, and suddenly has 80; I hope it's just a blip. Two countries are on the same track as yesterday: Australia, U.K. This is not a good thing, but not as bad as doing worse. The rest of these regions have shown at least a little improvement, thanks to tightening controls on the pandemic: U.S.A., Italy, France, Germany, Malta, Thailand, Norway, Brazil, Ontario, Malaysia, Mexico, Singapore.

Stay safe, everyone.

2020-03-23

Today's numbers: U.S.A. (14), Spain (16), Italy (20), Germany (21), Australia (22), Malta (22), Canada (23), France (24), Brazil (25), U.K. (26), Thailand (28), Norway (30), South Africa (30), Ontario (34), Malaysia (41), Mexico (41), Singapore (48), Denmark (55), Iran (64), Japan (164), China (10,168).

The U.S. reported new case rate looks like it has actually been decreasing over the past four days from the 40%s down to the 30%s. Today's is actually 27% as reported now, but there are usually additional reports that come in overnight, so that number is likely to go up. But still, it looks like measures to prevent spread are starting to have an effect, taking the doubling rate from once every two days to once very 2.5~3 days. In the current climate, you could call this good news.

There's a big blip in the Canadian numbers, reportedly because the province of Quebec has started accepting test result numbers from hospitals where they were previously only counting tests processed centrally. So that means that the situation wasn't as good as we thought before. Things like this happen all the time though, which is one reason I average the rate over the last four days.

In the province of Ontario, the daily rate has been remarkably steady at about 18% for three days. This is good, in that it's not going up, but it’s still a doubling rate of four days. Until today, we still had a lot of unnecessary activity in the province that was resulting in contagion. I'm glad that the province's announcement today has persuaded one of my friend's employers to finally shut down for the duration.

The rest of the countries I'm monitoring haven't had any major changes in the past day. That means that if they were doing a good job of bringing the epidemic under control (China, Japan), they are still doing so; and if they aren't (everyone else), they should be doing more now to do so.

2020-03-22

Today's numbers: U.S.A. (13), Spain (17), Italy (18), Germany (20), Brazil (22), Australia (24), Malta (25), U.K. (25), France (27), Thailand (27), Canada (29), Norway (29), Mexico (34), Ontario (34), South Africa (36), Malaysia (44), Denmark (47), Singapore (51), Iran (66), Japan (164), China (10,482).

The U.S. daily new case rate (or doubling time) remains more or less the same at 43% (or doubling faster than every two days). I've added Brazil, so that there's at least one other country in the same ballpark (38%). Spain, Italy, Germany are actually doing okay on the new case rate with their last few days all being in the teens (%) or lower; their day numbers are high because they all have a bigger proportion of their population infected already (1 in 1,000 in Italy), so they don't have as far to go. Thailand is in the opposite situation: they just had a big jump in their reported cases, but they were starting off with so few cases that their situation doesn't look as serious.

Canada and the province of Ontario have had their new case rates drop significantly over each of the last three days, as social distancing measures take effect. The daily rates are down in the 10-15% range now, so there is still work to do.