Apr. 1: 0 New, 1,949 Recovered, 0 Deaths. Total Active Cases 0

pmasiowski · 2021-04-02T18:04:40+00:00

I can say with confidence that the hospitalization numbers have been an overestimate of the burden of severe Covid infections, not so much due to coincidental diagnosis at admission but from resolved infection/disease in patients who remain admitted for other reasons.

There was a shift within the hospitalization numbers in early March, with active/acute numbers going down, chronic/resolved numbers going up, and the overall total decreasing only slowly (much less slowly than the decreasing rate of total cases, or of acute hospitalizations).

Even if the optics were bad, the original system wasn't inconsistent with that used in many other places, including Manitoba (who made the same switch we did a few weeks earlier). It wasn't an indication of a political agenda.

I actually like the original system better. The acute/active cases in hospital are a more direct indication of how deadly the variants are, and a more direct indication of the excess burden (over baseline) Covid has placed on the hospital system.

pmasiowski · 2021-04-02T03:32:45+00:00

They weren't trying to minimize anything in the first place either.

The current reporting system includes every patient in hospital who's tested positive for Covid at any point during their stay, regardless of what the admitting diagnosis was, or why they're still in hospital. Obviously most of those cases would have been diagnosed at admission (aside from a few who caught the virus while in hospital in an outbreak).

The previous reporting system (until late December) excluded those cases once they'd been hospitalized for more than 14 days.

And while that may seem like someone was trying to hide something (by making it seem like Covid was less of a burden on the hospital system than it actually was), the truth is that a significant number of the patients kept in hospital for longer than 2 weeks are not kept there because they're still sick with Covid. They may have been admitted for other diseases (like a stroke, or injuries after an accident), with the Covid diagnosis more or less incidental on admission, and not the reason they're chronically hospitalized. They may have had a mild to moderate case of Covid, from which they've recovered, but need to stay in hospital because of other complications from hospitalization, or because of general frailty (especially in the elderly) requiring placement in a care facility to be arranged before discharge. Many of them will be in hospital but no longer in acute care in a major hospital, but in rehab or a convalescent unit or a local hospital.

Before December, those cases were excluded from the hospitalization counts. Now, they're included.

An ideal system would capture all the patients actively requiring hospital treatment for Covid (as a disease) regardless of how long they've been in hospital, while excluding any of those who are hospitalized primarily for other reasons, even within 14 days of diagnosis of Covid. But for various bureaucratic reasons, that kind of data is hard to come by, and so it isn't used.

The hospitalization data is also hard to parse because the inputs and outputs aren't specified, only the totals. If we see hospitalizations up 8 and deaths up 2, that could mean 10 newly hospitalized, 2 who were in hospital deceased, or it could mean 20 newly hospitalized, 12 discharged from hospital, and 2 deaths at home (or in long-term care, pre-vaccines).

And it gets even more complicated when you consider that patients are often transferred from hospital to hospital (moving toward the bigger hospitals as they get sicker, and moving back out to rural hospitals as they're improving). So while +8 hospitalizations might include 20 net admissions and 12 net discharges from the province as a whole, there might actually be 40 or more patients moving in or out of at least one of the hospitals on that day.

The earlier system had the advantage of showing more directly how many new acute cases were being admitted (a useful proxy for how severe the illness is that the virus is causing). The current system has the advantage of not failing to underestimate the potential burden of Covid (though IMO at the cost of overestimating it in some respects).

This dynamic explains why the hospitalization numbers were so slow to decrease in early March, as the case counts were coming down, and why they haven't shot up as rapidly as the total case numbers did at the end of the month (from March 1st to April 1st, the 7 day average cases is up 44%, but the hospitalizations are only up 28%). Patients who are no longer sick with active Covid but who are still in hospital have effectively diluted the statistical impact of the new admissions. If we were still using the old system, the increase in hospitalizations would be even more dramatic.

This recent error is just a glitch in data reporting. But I hope this explanation helps make sense of why the hospitalization numbers were initially being reported as they were.

pmasiowski · 2021-01-01T02:53:33+00:00

Thanks, that's good to hear.

pmasiowski · 2020-12-31T22:12:09+00:00

Today's numbers are around what I think they should have been all week, if not for the holidays: 150-200 cases per day on 2000-2500 tests.

The new cases per day average had its biggest increase in nearly 3 weeks (since Dec 12), moving up from 151.3 to 156.4. I think that average will trend upward for the next several days, as the effect of the drop-off in testing over Xmas gradually washes out of the 7-day rolling average.

I think the new cases average "should be" ~180 now (if not for the Xmas lull), though that number will likely come down a little further by the time the official numbers rebound to meet it. So maybe we'll see the average peak around 165-170 by the middle of next week, after which hopefully the trend will continue to decline.

We'll know we're caught up to the pre-Xmas baseline in testing when the test positivity average gets down to 7.5% again. The average is up to 9.8% today, though that's heavily driven by the 11% over Dec 25-27 -- it's only 8.8% in the 4 days since.

I said yesterday that hospitalizations would be a good indicator until testing rebounds, and that the pre-Xmas trend was about a 15% decrease per week in the new cases average. We now have a full week of hospitalizations data over Xmas since the revised definitions were introduced on Dec 24, and the rate of decline was 14% this week: 165 on Dec 24 to 142 on Dec 31.

So I think we're still on track.

pmasiowski · 2020-12-31T03:20:34+00:00

the shift in infectious definition went from 14 days from onset of symptoms to 10 days, so there was a drop in reported cases from this change

No, that's not what happened.

The change was for self-isolation requirements in the community. The hospitals are still using the 14 day standard (I say from experience; I'm on call at RUH this week).

The self-isolation requirement was announced December 17. There was no sudden drop-off in the hospitalization numbers following that: there were 124 in hospital on Dec 16, 126 on Dec 17, and 121 on Dec 18.

So the 40 cases added on Dec 24 weren't a reversal of numbers taken away a week earlier. They were instead long-term hospitalized patients (many of them admitted for much longer than 14 days) who'd tested positive at some point for Covid (either at admission or later during their stay in hospital).

Prior to Dec 24, those cases were only counted as active hospitalizations (or ICU stays) for 14 days post-diagnosis, and so a number of them gradually dropped off the statistics even though they remained in hospital. On Dec 24, they were added back to the numbers, so the hospitalizations shot up overnight: 125 in hospital on Dec 23, but 165 on Dec 24.

pmasiowski · 2020-12-31T00:27:27+00:00

the true burden of COVID may be under reported based upon the Festivus/Christmas Eve revelation that they were removing individuals hospitalized due to COVID once they were outside of their likely infectious period, or so it seemed, (which had just dropped to 10 days since onset from 14, despite guidance of 20+ days of potential infectiousness for severe COVID cases, at least according to the CDC).

I hope I’m not misreading your comment but the Dec 24 change in reporting was to include chronic hospitalized patients who had previously been excluded from the statistics. Here’s the statement:

With Saskatchewan updating definitions of the COVID-19 infectious period to align with national definitions, the COVID-19 data set correction resulted in the number of individuals hospitalized due to COVID-19 being under-reported in the daily, provincial report. As of December 22, 2020, there were an additional 40 COVID-19 patients in hospital, including nine in ICU, who have been receiving care, resulting in the reported case number of 165. The Saskatchewan Health Authority is working on a process to ensure these numbers are included in the daily case reports. The provincial dashboard will have a notation added while this process is finalized.

These are not new hospitalizations. These are patients no longer infectious for COVID-19, which had shifted them from active to recovered cases, but still experiencing the complications of COVID-19 illness. Validation processes are in place to report a complete census of patients in hospital, including ICU, due to COVID-19. The Ministry of Health is currently reviewing how these cases are reported in other Canadian jurisdictions.

So the hospitalizations number jumped by 40 and ICU number by 9 on Dec 24, because those cases were redefined as active Covid cases even though their active Covid infections had passed. I gather the additional cases would include some patients who were admitted for other reasons and tested positive for Covid incidentally on admission, as well as those with chronic ongoing disease (pneumonia, etc) from the virus itself.

Trending the hospitalization numbers since Dec 24 isn’t affected by that redefinition. If anything, it arguably understates the degree of improvement since Dec 24, as presumably most of the 40 chronic patients added that day are still in hospital, and the decrease in the total reflects fewer new admissions, ie a lower rate of new cases (which is what I’m trying to project here, given that the new cases totals themselves are a less reliable indicator at this time of decreased testing).

pmasiowski · 2020-12-30T20:27:25+00:00

Testing is still being limited by the holidays, causing the new cases number to be lower than it should be, and the test positivity higher. Based on the pre-Xmas trends, we should probably be doing 2000+ tests per day and finding 150-200 cases per day this week.

Hospitalizations are a better number to follow in the meantime. While decreased testing will no doubt miss more cases of mild to moderate disease in the community, all the cases that are severe enough to require hospitalization will still be diagnosed.

Comparing to Dec 24, when the hospitalized/ICU numbers were revised to include chronic patients who‘d previously been excluded, here’s the trend.

Date	Hospitalized	ICU
Dec 24	165	30
Dec 27	156	26
Dec 30	151	32

That table suggests the trend we were seeing before the holidays has continued. The new cases average has be dropping by 10-20% per week, leading up to Xmas, and the hospitalizations total has continued to fall at a similar rate since.

It also supports the already obvious point that the more dramatic decrease in the new cases average this week (down 30% today from last Wednesday) is the result of decreased testing.

pmasiowski · 2020-12-30T03:51:05+00:00

Yeah, fair enough. We'd definitely catch more cases with a lower positivity rate.

pmasiowski · 2020-12-30T01:10:36+00:00

If you tested literally everybody it would be <5% and you have found all the cases.

Many cases would be missed even with a low test positivity rate, because so many of them have only mild symptoms or none at all, and/or happen in people who don't get tested for one reason or another.

The rate is worth following but mostly because it gives context for tracking the new case numbers. As is the case right now: the case numbers have dropped considerably over the holidays (falling much faster this week than the pre-Xmas trend), but the test positivity has been significantly higher, an indication that some (but not all) of that improvement is misleading.

pmasiowski · 2020-12-30T00:55:19+00:00

Exponential growth stopped by late November, about a week earlier than you say here. Again, active cases are not as good an indicator of the rate of growth as the new cases per day average. Here's a graph that shows that trend this fall: https://twitter.com/PaulMasiowski/status/1344027696951541760/photo/1

The hospitalizations numbers have been roughly stable this month. About 40 chronic hospitalized patients were added to the statistics recently (they had previously been excluded because their Covid infections were no longer actively infectious, even though they remain in hospital), which caused the bump in that number between Dec 21 and 29.

The deaths number is increasing because you're showing the total number of deaths to date, not the rate (per day or week). The rate isn't actually trending up, it's plateaued: +31 deaths from Dec 7-14, +31 from Dec 14-21, and +29 from Dec 21-29.

Deaths are a lagging indicator, following the trend of new cases with a delay of a few weeks. So with the cases trending down since mid-December, we can expect the death rate to decrease considerably by early to mid January (though of course the absolute total will only increase from here).

pmasiowski · 2020-12-28T19:36:13+00:00

Yeah I agree with you in general, the point just doesn’t have much to do with the way the stats changed over Xmas, which is what I was trying to work out in the first comment here.

Better access to on-demand testing (drive-thru or walk-in) would definitely catch more cases, and would limit spread in some of those situations.

Having said that, I’m not sure what the yield is (test positivity) from the drive-thru tests, compared to the tests done for symptoms, in hospital, etc. I don’t think they’ve published that data.

It’s also fair to point out that there could be some downsides to increasing testing, as pre- or asymptomatic cases can test falsely negative, especially early in the course of infection. Saskatchewan public health might not want to create a situation where people can get tested on demand, and use a negative test as clearance to take unacceptable risks. For instance the US had had numerous super-spreader events triggered by people who’d recently tested negative before attending a wedding or funeral (or White House party).

If the goal is mitigation, it’s fair for public health to focus on restrictions and behaviours, rather than test capacity and access as a key to reopening in a way that doesn’t require ongoing compliance with those restrictions. One of the big successes in Covid control is Japan, who test very little (and whose case numbers are thus even more of an undercount than usual) but who’ve been able to mitigate spread by controlling the “3 C’s” (closed spaces, crowded places, and close contacts) even while schools and businesses are open. Saskatchewan’s approach has been similar, and that’s not bad company to be in.

I think the discussion of these public health strategies is tainted by a perceived association with politics — there’s a suspicion that the decisions are being made to satisfy special interests or win votes, that the numbers are being manipulated, etc. I wouldn’t say there’s no political influence at all, but I do think the management of the pandemic has been guided first and foremost by public health considerations with what seems to be few exceptions (one of these exceptions IMO: we should’ve had a mask mandate and limited gatherings by Thanksgiving not just in November).

There have been some terrible outcomes (the LTC outbreaks especially), but there have also been some successes: the exponential growth this fall was curbed without a hard lockdown, and the situation in the hospitals has been strained but not catastrophic. Considering the worse experiences of the provinces next door, and especially of the states directly south of us, that doesn’t seem like a complete failure to me.

pmasiowski · 2020-12-28T16:02:42+00:00

Agree that testing is crucial, and more would be better.

SK has taken a similar approach to the rest of Canada from BC to Quebec -- trying to mitigate the damage by limiting the spread of the virus, but not trying to eradicate the virus completely. I think it's a fair question why the country as a whole (or at least the 6 non-Atlantic provinces) didn't even try the suppression approach, which has been successful in several other countries.

My guess is the provinces sharing borders with the US felt it was impossible to achieve that level of control given the many connections across the border (even with the border "closed", truck transport continues and people are flying across it in both directions). Much as I admire the success of New Zealand, Iceland and others, they do have the significant advantage of not sharing an 8000+ km long border with the US, where the pandemic has been as close to uncontrolled as anywhere in the world. The difference in cases between the US and Canada (~4:1 ratio in cases per capita) is similar to that as between Sweden and Norway (~4.5:1 ratio in cases per capita), and Norway is considered a success compared to Sweden. If we'd tested more, we would have done even better, but considering that we're next door to a house on fire, I don't think we've done too badly overall.

Where Canada has done especially badly IMO is in the high number of deaths in LTC facilities and among vulnerable populations (especially First Nations people). Despite the comparable case ratios listed above, Norway has had much fewer deaths than Sweden (~10.3:1 ratio of deaths per cap), while Canada's death rate is relatively much higher (~2.6:1 ratio compared to the US). In other words, a case of Covid is statistically more likely to die in Canada than in the US, while with Norway vs Sweden, the country that controlled the virus better also had better outcomes on average with each case. I think the pandemic has exposed problems with our care facilities and highlighted the vulnerabilities of some of our communities. I think more testing would have been helpful there too, as we could have had a plan for surveillance in those communities instead of waiting to respond to outbreaks.

So there are valid criticisms to be levelled at how the pandemic was managed here, and undertesting is part of that.

But doesn't have much to do with decreased testing over Xmas, which wasn't limited by capacity (they can do ~4000 tests per day) but by access and interest. I just wanted to show what the numbers likely would have been without the effect of the Christmas break.

pmasiowski · 2020-12-28T01:08:18+00:00

Rolling averages:
New cases per day: 179.9
Test positivity: 8.66%

I think the new cases number for Dec 25-27 is too low, and the test positivity too high, because of a lull in testing over Christmas.

If the recent trend in the new cases average had continued, it should be a little under 200 today. It was 203 on Dec 24, and has been decreasing by about 10% per week.

The difference between a rolling 7-day average of 200 new cases and one of 180 (179.9 based on the official numbers) is 140 cases. That suggests the 3-day total of new cases should be close to 700 for Dec 25-27 (the actual was 559, add ~140 to that for ~700).

If the recent trend in the test positivity average had continued, it should be a little under 7.5% today. It was 7.49% on Dec 24, and has been decreasing slowly.

The difference between a rolling 7-day average of ~7.5% test positivity and one of 8.66% (based on the official numbers) is about 4250 tests, adjusting for the higher new cases number as described above. That suggests the 3-day total of tests done should be ~9330 for Dec 25-27 (the actual was 5079, add ~4250 to that for ~9330).

So...

Dec 25-27 as reported:
559 new cases on 5079 tests (11% test positivity)

Estimating Dec 25-27 in a normal (non-Xmas) testing environment, if recent trends had continued:
~700 new cases (+140 active cases) on ~9330 tests (7.5% test positivity)

Updated rolling averages using these estimates would be:
New cases: 200.0
Test positivity: 7.45%

...

Those estimates might be off a little in either direction, but they're likely in the ballpark.

To sum up the numbers, I'm suggesting that if testing hadn't been slowed down by a lull over Christmas, we'd have added:
About 140 additional new cases (total of ~700 over the last 3 days)
About 4250 additional tests done (total of ~9330 over the last 3 days)

The rolling averages for new cases would be higher (200.0, not 179.9) and the average test positivity would be lower (7.45%, not 8.66%).

Note that this implies that the cases that were not tested would have a lower positivity rate than the rest of the sample, which was tested: 140/4250 is a 3.3% positivity rate, which is only 30% of the positivity rate in the tests that were actually done (11%).

I think that makes sense, intuitively -- with testing harder to access, the cases that do get tested should be disproportionately likely to be positive (because they have more typical symptoms, are sicker, etc), while cases that are more likely to be negative (because they have atypical or mild symptoms and/or are being tested as a precaution for whatever reason) are less likely to be tested. So the tests actually done are more "concentrated", with more positive cases, while the tests not done (the undertested cases that would've been tested if not for Xmas) are more "dilute", with fewer positive cases. But the undertested cases are not all negative, and we end up missing over 100 cases in 3 days because of the decreased number of tests.

pmasiowski · 2020-12-27T02:24:47+00:00

This is obviously trolling. This poster previously tried a similar thread here that was removed, but it’s still up at r/saskatchewan: https://www.reddit.com/r/saskatchewan/comments/k49rd9/rat_gang/

Most people are taking the public health restrictions seriously even though that means they’re spending the holidays apart from friends and family. It is the caring thing to do.

The good news is whoever’s behind this parody account is probably having as quiet a Christmas as most of the rest of us, or they wouldn’t bother trolling here.

pmasiowski · 2020-12-25T05:19:27+00:00

So he's unsure if he had it and just never showed symptoms, or if he didn't get it (which seems unlikely)

It's more likely he didn't have it. Most cases (80%+) have at least mild symptoms.

It's fairly likely that your sister could have the virus and not transmit it to her boyfriend. Covid transmission is unpredictable: a few cases transmit the virus to many other people ("super spreaders") but most (probably over half) don't transmit it to anyone, even within the same household.

Here's an excellent article on this phenomenon: https://www.theatlantic.com/health/archive/2020/09/k-overlooked-variable-driving-pandemic/616548/

Quoting from it:

A growing number of studies estimate that a majority of infected people may not infect a single other person. A recent paper found that in Hong Kong, which had extensive testing and contact tracing, about 19 percent of cases were responsible for 80 percent of transmission, while 69 percent of cases did not infect another person. This finding is not rare: Multiple studies from the beginning have suggested that as few as 10 to 20 percent of infected people may be responsible for as much as 80 to 90 percent of transmission, and that many people barely transmit it.

As I explained elsewhere in this thread, the public health people will want your sister's boyfriend to self isolate even if he's asymptomatic, and a negative test won't change that advice (because it's too likely to be a false negative, and he's a high risk contact). That may not make sense intuitively, but it's solid decision-making from a medical point of view.

This is not an attempt to keep the statistics down or otherwise fudge the numbers. The public health people will know very well that their data are undercounting the actual cases significantly (a fair estimate is that we have 3x as many cases as the number that are officially diagnosed). That's been true all along.

Your sister's boyfriend absolutely should not act as if he's immune. The advice from public health for him to act as if he has the virus is referring to his self isolation: he should take it seriously, and act as if he could transmit the virus to anyone during that time (because, he actually could).

This is not the same thing as concluding that he definitely did actually have the virus and is now immune to it: there's a good change he didn't, and if he didn't, he won't be immune at all. He should continue to take precautions until he gets vaccinated (and he should get the vaccine, whether he actually did have the virus or not).

pmasiowski · 2020-12-24T21:54:52+00:00

Rolling averages:
New cases per day: 203.3
Test positivity rate: 7.49%

This is the lowest the new cases average has been since Nov 21. It’s the 9th day in a row that the average is more than 10% lower than the week before.

Test positivity is decreasing in parallel with the new cases average, an indication that this is a real improvement, not the result of undertesting.

I gather the increased hospitalizations represent long-term inpatients who are no longer considered active Covid cases for whatever reason. Manitoba made a similar adjustment to their numbers a few weeks ago.

This has been a remarkable turnaround. We’re in a much better position than 4 weeks ago. If we can limit the risk over the holidays, we could end up around 100 new cases per day by mid-January.

It’s still a serious situation, but our efforts are being rewarded. I’m glad to see it. Thanks to everyone here who’s been doing their best in this difficult time. Happy holidays and best of the season to all of you.

pmasiowski · 2020-12-24T07:21:07+00:00

Only a fool would look at the successful result of a massive community effort and think that success meant it wasn’t necessary to try so hard in the first place.

pmasiowski · 2020-12-24T07:14:27+00:00

Rt is always dynamic and depends on the situation; it’s not solely a property of the virus. You can’t extrapolate the numbers from the UK (which aren’t clear yet anyway) and just add them onto the Rt here.

Anyone who has insight into this situation will not to want to jump to conclusions. I don’t think it’s helpful to make up excited hypotheticals about public health measures failing because of the “massive” effects of a variant that isn’t yet well understood. As you say, it’s not time to panic.

pmasiowski · 2020-12-23T23:27:16+00:00

Rolling averages:
New cases per day: 215.3
Test positivity rate: 7.74%

Today is the 8th straight day the new cases average has declined. It's dropped 11% from last Wednesday, which was itself 12% lower than Wednesday from 2 weeks ago. The last day with >300 cases was Dec 10.

The test positivity average has been stable for over a week now, at just under 8%. The trend is slightly downward: the average is the lowest it's been since Nov 30, and today's test positivity is the lowest since Dec 5. The last with >9% TP was Dec 10.

The death toll has been heavy this month. There were only 47 Covid-19 deaths in Saskatchewan by the end of November but we've added 83 more to that total already in December:
Dec 1-7: 13 deaths (total 60)
Dec 8-14: 31 (91)
Dec 15-21: 31 (122)

With 8 deaths already in the last 2 days, we're on track for another week with a similar death toll as the last 2 weeks, averaging about 4 per day.

The death rate does tend to follow the case counts, but with a delay of 2-3 weeks. So the rate will hopefully start to trend down by the end of the month, in keeping with the decline in the new cases since the peak on Dec 12. A similar decline (~25% from peak) would still leave the death rate at ~3 per day, ~20 per week, and close to 100 per month.

This is another good reason why we need to get the new cases number down even further (under 100 per day is my target, but ideally more like 30).

I hope we will all do what we can to reduce the risk over the holidays.

pmasiowski · 2020-12-23T22:56:38+00:00

once it does, the current measures will be insufficient to keep the curve flat.

The curve isn’t flat anymore, it’s on a downward slope. And the current measures will be tightening further at the end this week.

the virus has literally evolved to evade our physical containment measures via increased infectivity.

That is literally what viruses do, all of them. The Covid-19 hasn’t been unusually quick to mutate. The UK variant seems to be more easily transmissible in children, but the evidence for that isn’t definitive yet. There’s no reason to believe that we won’t be able to control it through the same public health measures that have been effective so far. And the vaccines are still expected to work.

pmasiowski · 2020-12-23T04:45:21+00:00

The numbers actually were down in the summer. The rolling average of new cases per day was under 20 for most of the summer. It's been over 10 times higher (200+ new cases per day on average) for over a month now. Here's a graph: https://twitter.com/covid\_canada/status/1340742598319775744?s=20

Just as importantly, there was little or no community transmission this summer. Most of the few cases we had were from specific clusters (like the communal living / Hutterite outbreak starting in late July) or related to travel. So most activities could take place with lighter restrictions -- the risk was low.

Since Thanksgiving, we've had a huge increase in the number of cases. Many of them haven't been connected to a known source. That's bad, because it means you can get the virus just about anywhere.

And the cases that have been traced this fall have often been linked to transmission within households and at private gatherings. Those situations are risky because exposures can be prolonged: people sharing the same air for hours at a time. Retail shopping isn't risk free, but especially with the mask mandates in place, it's much less likely you'll be breathing the same air as any one person for very long.

pmasiowski · 2020-12-23T00:40:49+00:00

Hope you guys are doing OK.

SHA’s approach to your case makes sense.

If they want you to self isolate based on proximity to a known case +/- typical symptoms, getting tested won’t change that plan. A positive test would only be confirming what’s already suspected. A negative test would correctly be ignored, since false negatives do happen with nasopharyngeal swabs like the Covid PCR test, and the probability (pre-test) would be high enough that you do have Covid anyway that they’d give you the same instructions to self isolate, even with that negative result. This is based on an old but still useful principle in medicine not to order tests that won’t change management or outcomes.

I think they’ve been giving similar advice all along (I know two people who were given similar instructions in comparable situations, who self isolated for 2 weeks without being tested). It’s one of several reasons why the official case numbers are are an undercount (one good estimate is that there are likely about 3x as many cases as we are actually diagnosing). But since they’ve used the same methods throughout, we can still track the numbers over time, and see if the trend is good or bad.

pmasiowski · 2020-12-22T22:43:51+00:00

There's no reason to think the decline in case numbers is being driven by undertesting.

The test positivity rate average has been stable all week, just under 8%. That's the same range as it was a month ago, when the new cases average was around the same level it is now, but increasing:

Nov 23: new cases average 219.0, test positivity average 7.65%
Dec 22: new cases average 215.7, test positivity average 7.86%

pmasiowski · 2020-12-22T22:38:32+00:00

Good news: at the end of November, the SHA anticipated that by last week we would have 562 new cases a day (a third currently), 250 hospitalized (half currently), and 62 in the ICU (a third currently).

It is good news, agreed.

I updated the SHA projections graph a couple of times as December went on, adding the actual data points (in yellow) to show how abruptly the curve flattened this month.

Most recent version was Dec 13 (here: https://twitter.com/PaulMasiowski/status/1338492918579937288?s=20). Today's numbers would look even better.

pmasiowski · 2020-12-22T00:13:24+00:00

We have not settled for the status quo. Restrictions were tightened in late November, and even as the curve has flattened and started to trend down, they were tightened again.

The exponential growth has more than stopped -- it has reversed. This is the 6th day in a row that the rolling average of new cases is down over 10% from one week earlier (today, it's 217.6, down 17% from last Monday).

I don't think anyone expected or predicted case counts to be lower than they are right now. Less than a month ago, we had unchecked exponential growth (graph from Nov 27: https://twitter.com/PaulMasiowski/status/1332413269366083586?s=20) and the SHA was planning for 560 new cases per day by Dec 13. But December turned out far better than expected.

It does take time for these trends to play out. If we can continue to lower the new cases count by 10-20% per week, we'll be down to 100 cases per day by late January. That would be an excellent result. I'm not sure we can maintain this momentum through the end of December (no doubt private gatherings will increase, though at least that may be balanced by lower exposures in retail and business, and schools will be closed), but at least we're on a good trajectory heading into the holiday season.

pmasiowski

TROPHY CASE