Kansas COVID-19 Update, Week 3

Updated Aug 3: The test positivity rate cited below (18.6%) appears to be an error. After taking a deeper look at the Johns Hopkins data, it includes one day (July 27) in which test positivity was reported to be 109.7%. This is obviously impossible (you can't have more than 100% of tests come back positive), so there's something wrong with the data on that day. Test positivity on the other days in the rolling average are 11.2%, 10.8%, 10.8%, 11.6% and 12.5%. So the true number is probably somewhere between 10.8% and 12.5%, which is closer to what it was last week. Still not good, but much better than 18.6%.

The format has changed a bit with this week's Kansas COVID-19 update. Only one of my key stats was "bad" compared to the week before, but it was SO bad that it has skipped right to the "ugly" category. It is a truly shocking number, and one I hope is a fluke, or a data error. As a palate cleanser, I've included another "bonus" section on a single county.

The Good: Once again, Kansas' reproduction rate, or Rt, has ticked down a bit, now to 1.07. Until there is a vaccine or an effective treatment, getting that Rt below 1.0 remains our best chance of containing the virus. (Rt below 1.0 means every infected person spreads the virus to fewer than one other person, on average, which would cause COVID-19 to slowly die out for lack of new hosts. Rt above 1.0 means the virus' spread is increasing). If Rt is decreasing, that probably means more people are wearing masks and social distancing. 

The Neutral: ICU admissions were stable this week, with at least 98 COVID-19 patients in intensive care and 36% of beds available on July 30 (the same numbers as on July 23).

The Ugly: According to Johns Hopkins, the percentage of COVID-19 tests that came back positive in Kansas jumped from 11% last week to 18.6% this week. If that's accurate it means Kansas is not only far from the World Health Organization's standard of 5% or less, but it's tied with Arizona for the fifth-highest test positivity rate in the country. It's also disheartening in that it means we're probably missing a lot of cases and that drop in the Rt might be a mirage caused by hidden infections. 

A quick clarifying note: many Kansas media outlets, when they report test positivity rate, use the figure reported by the Kansas Department of Health and Environment, which is much lower (9.5%). But KDHE appears to be calculating test positivity based on the cumulative number of all tests in the state since the beginning of the pandemic (now almost 300,000). That's not wrong, but it does mean that the percentage isn't going to move much from week-to-week. I prefer to look at Johns Hopkins' number because they're calculating test positivity based on a rolling average of the last seven days of testing. That provides a more current snapshot of the situation, but it also makes the positivity rate more susceptible to weekly fluctuations in testing. 

For example, there has been a lot of press lately about long wait times for outpatient testing done at private labs (mostly Quest and LabCorp). Kansas depends heavily on those labs (they've recorded 70% of the state's positive cases, so far). If their results were really backed up last week and most of what was actually reported were results from hospital inpatient labs, that might skew the test positivity number higher (because patients sick enough to be hospitalized are more likely to have COVID than outpatients). But still, 18.6% is a number that should cause all of us to sit up and take notice. We need more testing in Kansas.

Bonus: At the end of May, Sedgwick County had its test positivity rate down to about 1%. But then the shops, restaurants and bars opened back up and the rate quickly ballooned to about 14% by July 23. Things were going the wrong direction. At one point in mid-July, Wichita's hospitals estimated they had only eight ICU beds available. But since July 23, the test positivity rate has made an abrupt downward turn and is below 12% and falling. What happened? Here's one theory: on July 8, the Sedgwick County health officer ordered residents to wear masks in public areas. Almost exactly two weeks later (the maximum incubation period of the novel coronavirus) the county's test positivity rate began to go down. It's impossible to prove that the mask order caused the downturn, but the timing matches up. Sedgwick County still has a long ways to go, but it's now trending in the right direction, and, as I wrote last week, trends are everything with outbreaks of infectious disease.

Kansas COVID-19 update, Week 2

Based on the latest available data, Kansans seem to be spreading COVID to each other a bit less than last week, which is good! But we're still spreading it too much to change the trajectory of the outbreak from one that is growing to one that is shrinking. And we're starting to see evidence of that in our hospitalization numbers.

(Read to the bottom for bonus content on one county that HAS turned things around).

The Good: Our reproduction rate has ticked down ever-so-slightly from 1.12 to about 1.09 or 1.10. The reproduction rate, or "Rt" (or "R0"), remember, is the number of COVID-19 infections that each infected person causes, on average. When it is above 1.0, the outbreak spreads. When it's below 1.0, the outbreak shrinks. We can reduce it by doing things like social distancing and wearing masks. At our current Rt, the number of COVID-19 cases in Kansas will double about every 27 days. But we're not that far away from making our case numbers shrink (like we did in May). It's been hard to pin down just how effective masks are at preventing the spread of COVID-19. But a new analysis of all the mask studies available determined that if 95% of people in a given area wear masks, it reduces the spread of COVID-19 in that area by at least 30% (and the authors say that's a conservative estimate). That 30% reduction would be more than enough to get Kansas' Rt below 1.0.

The Bad: After weeks of increasing COVID-19 cases, Kansas hospitals are starting to feel more strain. Earlier this month, we had about half our ICU beds available. As of July 23, we had 36% available. That's still plenty of capacity statewide, but it's not spread evenly, and the overall trend is bad. In three weeks, the number of ICU beds taken up by COVID-19 patients doubled, from 49 on July 1, to 98 on July 23. Remember: hospitalizations are a lagging indicator (and ICU admissions tend to lag even more). That means that even if we take action TODAY to reduce COVID-19 spread, hospitalizations will almost certainly continue to rise for another two or three weeks. If you wait until your hospitals are full, you've waited too long. That's when things that were previously unthinkable happen, like an overburdened hospital in Texas preparing to decide which patients they will turn away and send home to die. To be clear, we're not near that point in Kansas right now. But two months ago that hospital in Texas wasn't either.

The Ugly: We're still not testing enough. According to Johns Hopkins, our test positivity rate (the percentage of COVID-19 tests that come back positive), has risen from 10.7 to 11.0%. That puts Kansas among the top 10 states in a stat we do NOT want to be top 10 in. Remember: the World Health Organization recommends a test positivity rate of no more than 5% to be reasonably confident you're identifying most cases of COVID-19. In Kansas, test positivity rates remain persistently high (about 17%) in Wyandotte County in particular.

Bonus: It is possible to turn things around, and turn them around quite quickly. For evidence, look at Douglas County. Douglas County, home to the University of Kansas' main campus, was recording steady increases in new COVID-19 cases from mid-June until early July. Then, almost as suddenly as the rate of new cases spiked, it began dropping quickly. What happened? Around the end of June, the local government voted to close bars and require masks in public places. For about a week, the rate of new cases kept going up (because a lot of people had already been exposed). And then it dropped, and has kept dropping for a couple weeks. Given the robust bar scene in Lawrence, it's likely closing that one industry had a bigger effect there than it would have in other counties. And Douglas County still has to be diligent, because its rate of new cases remains relatively high. But they've reversed the growth trend, and in tracking COVID-19 trends are everything. Remember that: these stats reflect a point in time — they're important, but it's more important to watch whether things are trending better or trending worse. Because in a viral pandemic, the trend is not likely to change unless there is a behavior change, like there was in Douglas County.

Kansas COVID-19 update, Week 1

Kansas is at an inflection point in the novel coronavirus pandemic. Our state weathered the first wave relatively well, and currently has one of the lowest COVID-19 death rates in the country.

But after an uneven county-by-county reopening of the economy in late May and early June, case numbers have been ticking up. This week we found out that Kansas was one of 18 states designated as "red zones" for COVID on an internal White House document based on the growth in new cases.

Raw case numbers are far from a perfect metric, because they can fluctuate a lot based on the amount of testing you do. So, every week (for an indeterminate number of weeks), I'm going to highlight some other metrics on this blog that hopefully will give us a better idea of just how we're doing in Kansas, and help people make decisions about how much they should be going out and exposing themselves to other people's germs. I promise to provide links to every number I cite, so you can go back and see the data for yourself. Here goes:

The Good:
Hospital capacity in the state is in good shape, overall. As of July 14, the CDC estimated that only about half of Kansas' regular inpatient beds and ICU beds were full. But this good news comes with a caveat: COVID-related hospitalizations have recently begun rising in the Kansas City area and in Wichita. Hospitalizations are a "lagging indicator" (they don't go up until cases have been rising for several weeks). Once they start to rise it takes at least two weeks for any behavioral changes to stop that rise. In other words, if you wait until hospitals are almost full to act, you've waited too long.

The Bad:
Our infection reproduction rate of approximately 1.12, shows that Kansans are spreading COVID to each other too much. The reproduction rate, often abbreviated "Rt" or "R0," is the number of new infections that each infected person creates. If the rate is at exactly 1.0, then every infected person only infects one other person and the outbreak doesn't get worse or better. The higher above 1.0 Rt goes, the faster the outbreak spreads. If you hold it below 1.0, you can starve the virus of the new hosts it needs to survive and slowly choke off the outbreak altogether. Germany has had good results tamping down COVID by focusing on this number: when reproduction rates rise above 1.0 in a given region, they put restrictions in place in that region. When it goes back below 1.0, they relax them. It's a proactive approach that helps them get ahead of outbreaks before they become problematic. What factors reduce the COVID reproduction rate? Avoiding crowds, social distancing, and wearing masks, especially when indoors. The Rt rate is notoriously hard to estimate, but multiple sources now peg Kansas' rate above 1.0. As long as it stays there, the outbreak will continue to grow.

The Ugly:
Our test positivity rate in Kansas is too high. Test positivity is the percentage of COVID tests that come back positive. It's a better measure than raw case numbers because it doesn't "penalize" you with higher numbers if you do more testing. In fact, the more testing you do, the lower the test positivity rate should be. In Kansas, however, it has climbed to 10.7%, the 11th highest rate in the nation. Anything over 10% is generally considered a "red flag" that means you're not testing enough to be reasonably confident you're identifying most cases. The World Health Organization recommends governments maintain a test positivity rate of 5% or less before reopening their economies. Data from some of the European countries that have been most successful at reopening without seeing a surge in cases suggests that the optimal threshold may be even lower — more like 1.5%. Kansas obviously has a long ways to go to reach either threshold.