Thursday, June 11, 2020

Protests Reveal Little Threat of COVID-19 in Outside Air: Why Is Seattle Still Restricting Park Access?

As I discussed in a previous blog, there is little evidence of transmission of COVID-19 in outside air, with a substantial and growing literature documenting the lack of risk for virtually any activity in the outside air.
Empty parks in Seattle

But now, there is even more compelling and powerful evidence of the lack of COVID threat in outside air, even in a worse-case situation:  the lack of surge in COVID cases following the large protests in Seattle and other cities.

The protests represent the opposite of responsible social distancing, with large crowds of hundreds or even thousands packed in close together.  

People are screaming, chanting and singing:  activities that are optimal for spraying virus-laden droplets into the air.  Many, but not all, of the protesters are wearing masks, with most of them using the less effective cloth ones.  And tear gas causes people to cough and expel large quantities of mucus and droplets.  If you want to spread a dangerous virus, you would think the protests are the perfect way to do it!



So if COVID-19 transmission was in ANY way effective outside, one would expect a major jump in COVID-19 cases to occur.  

The average period from exposure to symptoms is around 5 days and the protests started about two weeks ago--so there should be a major uptick of hospitalizations and active infections now if outdoor transmission is significant.

Has this occurred?  We now know the answer:  there has NOT been an upsurge in COVID-19 cases, and thus transmission outside has to be minimal to non-existent.

Let's look at the numbers!

King County, the center of the protests, has shown no peak in hospitalizations.



The percent positive tests at the University of Washington Virology Lab is shown below.  If the virus was surging the percentage would go up quickly.  Instead, it went down over the period with no rapid increase during the past week (some problem occurred on May 30th).



What about other cities with protests?   No spike in the percentage of positive tests at any of them (see below)
Courtesy of Willis Eschenbach

It is important to note that at this point we would expect a slow rise in the number of cases as restrictions are slowly lifted.    This has nothing to do with the protests.  Such a slow rise is found in epidemiological models (see below).   Most people have not been exposed to the virus, but prudent social distancing and wearing of masks can keep the situation in check.  Hospitals are not being overwhelmed.  In fact, they are quite empty.


The bottom line of all this?  With all the lack of social distancing and maximal ejection of droplets from people (from chanting, singing, screaming and dealing with pepper spray and tear gas), COVID-19 has not surged.

There is one obvious explanation for this lack of COVID uptick:  viral transmission is very minimal in the outside air where there is huge ventilation, where UV radiation is present during the day, and where humidities and temperatures are generally unfavorable.

The protests have facilitated a huge public health experiment and we now know that COVID-19 basically does not spread outside.  A result consistent with the research cited in my earlier blog.

But that leaves a major question:  why is the City of Seattle still putting up major roadblocks for the use of their parks?  Why are the parking lots of most parks closed?  Why are tennis court nets taken down?  Why are people being kicked out at  8 PM, being denied sunset walks at our glorious waterfront and view parks?  Why is picnicking against the law?  Why is the Seattle Park's and Recreation Department ignoring scientific evidence in continuing the closures?

Please Mayor Durkan, completely open the parks.  If you can let protestors roam the city in the thousands, even creating a new country on Cap Hill, can't you let the rest of us enjoy the parks, have a picnic with our families and friends, and allow the elderly and mobility limited a chance to enjoy the parks like the rest of us?  There is no place that allows better social distancing, healthful exercise and mental rejuvenation than our parks.  


At Seattle Parks picnicking or stopping to enjoy the view is forbidden to normal folks.


 But park personnel don't have to follow the rules and enjoy leisurely lunches with a world class view.



Some people might conclude the park was closed.  In Seattle, you have to read the fine print.




36 comments:

  1. The density of housing and the saftey measures employers take seem to have the biggest effect on how much the virus spreads. Los Angelas is seeing alot of virus spread because the cost of housing is so high many people have to live in a small housing unit. This is clear evidence to me that its not healthy or humane to pack so many people in such a small area but most jobs are in the city so many people have no choice but to live in unhealthy conditions. Also masks and social distancing at work would make a huge difference Arizona is seeing a big rise in cases because they have Republican Politicians that didn't require employers to take as many precautions as the democratic states. Keeping people inside all the time probably increases the virus spread rate alittle bit.

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  2. Well this is the same city where a Council Member let protesters in to City Hall and the Police Chief doesn't agree with the mayor.

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  3. Thank you Cliff, reading this was the second best thing that happened today. All the stuff going on and you stick with the science. I respect you.

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  4. Shhh... Let em believe what they want. I wanna savor the emptiness for a few more weeks...

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  5. The tennis courts still being closed really is frustrating and dumbfounding. We can gather in groups of 5 at restaurants now, but we can't play tennis (where we will almost always be 6+ feet apart) at a group size of 2 or 4...

    Tennis never should have been taken away.

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  6. Also ... you can't assume that everyone is going to get tested. Many people are still under the impression that tests are hard to come by. And they actually are less readily available in many counties outside of King, Snohomish, and Pierce. Not all the protesters live in King county.

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  7. Thanks, Cliff! This is great info!
    Makes me want to take my family and friends to a camping site to do some peaceful protesting while having burgers and beers.
    But this will make CNN and our Democratic leaders so unhappy, as they've been trying to tell us for months that COVID-19 is so awful that we should stay under house arrest at all times and obey, otherwise we would become silent killers.

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  8. Agreed! Tennis, and the stance the city has taken against it, is troubling. Those of us who have played it for decades know how healthy a sport it is to play. And play we will! In fact, I've been playing for a month in Seattle. There are people playing all over the city now. Fortunately, the courts never closed on the island I live on. No dictatorial mayors there.

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  9. I agree that parks should open, but I think it's too soon to know if the protests lead to a spike in transmission yet. Most of the protesters are younger and might not get sick enough to get tested.

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    1. Agreed.This article is premature. Hospitalization figures at this stage are almost meaningless. Hospitalizations in the groups that attend these protests in numbers do not occur immediately after infection, but rather several weeks later. Infections are more instructive, but it's still too soon. Give it another 1-2 weeks before drawing these kinds of conclusions. It's fun to be contrarian. But fun should not be the basis for making recommendations that could hurt people.

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    2. Bruce... I hardly think that letting folks watch the sunset or play tennis or use the parking lot instead of a long walk, would be "hurting people." Just the opposite. So if in two weeks there is no spike, you will support the call to open the parks?...I hope so..cliff

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    3. The time to symptoms averages 4-5 days for all ages.

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    4. And I've heard rumors of the opposite - specifically hospital workers claiming the most recent covid patients are protest-related.

      But in reality, it's much too early to draw any conclusions. Transmission takes time. And the data is delayed anyway. To confuse matters more, restaurants have now reopened, so any spike we see in the next few weeks could be due to that, and not the protests.

      It's stupid park usage is still discouraged, but drawing conclusions about the protests at this point is much too premature.

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    5. Cliff, I always appreciate a look at the data, and enjoy your reading your writing. But given your large readership and comments on important societal questions, e.g. COVID-19, I think you should be more careful. It may be still too soon to draw those conclusions about transmission during protests--as it was far too soon for you to say the curve of new infections was flattening on March 13th (https://cliffmass.blogspot.com/2020/03/panic-and-coronavirus-is-there-is.html). Your comments may have significant impacts, careful scrutiny is needed.

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  10. At parks, the issue is not so much coming close to people outdoors as it is sharing of facilities. With larger numbers of people not from the neighborhood, rest rooms and play sets will get used and there is a higher possibility of hand surface contact with contaminated surfaces. That's why I agree with Mayor Durkin's closure of the public facility portions of larger parks, because with local usage, people will be able to go home when they need to use the rest room.

    At my local park there has been, all through the shutdown, a lot of usage of the running track, outdoor basketball courts, and pickle ball courts, to the point where the non-physical distancing is uncomfortably close, but no issues. But the rest rooms and play area have been closed. As long as people are wearing masks (which hasn't been observed much until May) it should be fine.

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    1. But it appears that most infection is from contact with exhaled water droplets, not from contact with contaminated surfaces.In any case, keeping park bathrooms open means people can wash their hands.

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  11. Terrific blog, rooted in science and common sense. As a tennis player, I am tired and frustrated at Durkan and Inslee claiming "data and science" as the basis for these outdoor restrictions, yet completely ignoring data and science (just because they can show they are being extra cautious, and have the control to do what they want).

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  12. Or simply decide that you've had enough of this overbearing idiocy, and ignore the signs. I can tell you from recent experience that neither parks dept workers nor SPD give a damn who is in the park after 8 p.m. Sort of like those "essential trips only" signs everybody ignores on public transit.

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  13. What we need to be looking at is the 7-day moving average of death rate. It's declining almost across the board. There will be more infections, but if the death rate is declining, then that tells us about attenuation or the lowering of virulence.
    WA only: https://docs.google.com/spreadsheets/d/1EztQ69s80ATZj64WVOEx4eezYAWTKp2nppyHOyUEY58/edit#gid=1157182735

    World/US: https://docs.google.com/spreadsheets/d/1FXVgNrTbECcO8X4-hFXhJuqgE5sl-7ddU-IO2ciXCdU/edit#gid=275720644

    World death rate decline: https://docs.google.com/spreadsheets/d/e/2PACX-1vRcwR1LeyhdbSnKNfPNEmlDD-6pNy3WO4LVipG5gvZN8audLJ_btWUv8zLNzZN-Ox75OFyPLda9_uxQ/pubchart?oid=1399823394&format=image

    United States death rate decline: https://docs.google.com/spreadsheets/d/e/2PACX-1vTF-pAWvf3gfYtTzf8MVn90KoXc23uPW0ObrpQSF4q9M8P_FoLs3pzQMYgK6OeN2gDrAtD7Whsbw3Kp/pubchart?oid=296905222&format=image

    WA death rate decline: https://docs.google.com/spreadsheets/d/e/2PACX-1vTF-pAWvf3gfYtTzf8MVn90KoXc23uPW0ObrpQSF4q9M8P_FoLs3pzQMYgK6OeN2gDrAtD7Whsbw3Kp/pubchart?oid=296590487&format=image

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  14. Deaths peak about two weeks after hospitalizations peak.

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  15. As of today, June 2020 has been the wettest June at BLI since at least 2014.

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  16. Would be interesting to hear from epidemiologists.
    I am very unconvinced by the hospitalizations graph, skeptical you can draw ANY conclusion on transmission outside from that.
    So, what, 5% (high estimate, 100,000 people) of King county residents spend 10% of their time mingling at marches, mostly wearing masks which may be crucial. (WELL DONE THEM ON BOTH COUNTS!)
    If outdoor mingling increased the R_0 from 0.5 to 5 for this subgroup, would we see it in the data? I very much doubt it.
    First off, it can take longer than 5 days (Italy shut down March 12 and new cases peaked 2 weeks later).
    Since our local infection rate is low, we are now looking for a small effect on a small proportion of the population. So hospitalizations around 5 per day is nowhere near sensitive enough to say anything. Even the 30 or so out of 3000 positive carriers tested after marching is hard to interpret: 30 (plus or minus statistical error of 5 or 6) compared to what?
    The king County dashboard shows an infection rate of around 2 people per 100,000 per day.
    If marching increased that a factor of 10, that means about 20 marchers per day would get infected, or 0.02%. OK, I will give you 10x that, 0.2% or 200 marchers assuming they went to every march: So instead of 30 marchers out of 3000 testing positive, we would see 36, within the statistical noise.
    I don't need an epidemiologist to tell me that R_0 of 5 is a 5-alarm fire, and yet the data seem consistent with it.

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    1. Can you help us here with an overall concluding statement? Are you saying we need to wait another few weeks to see the damage or that there wasn't enough virus present to really spike the case counts significantly? Thanks!

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    2. Neil, this scientist, Trevor Bedford,
      Has his epidemiological thoughts at the link below,

      https://mobile.twitter.com/trvrb/status/1270109925557952512

      I don't necessarily support his theory.

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    3. B O B,
      Sort of both. We now have a (hard-won) low rate of infection,so don't expect to see a big average effect especially this quickly. It's in the nature of things that can grow exponentially that the initial effect may be very small. Eg, leave your milk out on the counter for a day. It will be fine. No need to keep it in the fridge!

      I do tend agree with Cliff's overall point about the parks should be clearly marked as open, with some caveats (masks, distance), but question the method based on the evidence available. As he knows, it's very hard to really know something in science!

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  17. Cliff,

    I agree that parks should be open later especially as the days lengthen. My suggestion is to reevaluate the limits in place and adjust accordingly.

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  18. https://komonews.com/news/local/uw-model-predicts-second-wave-of-covid-19-in-us-starting-sept-15?fbclid=IwAR3yd8Fw4J-Qwp_DxALbVNQV1hYMEGNouHe6NXL4hUIh027h3PSswLWpOtk

    It's not over yet.

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    1. " ...though the model predicts a range of 133,201 and 290,222 ..."

      That's a pretty sizable range -- and what assumptions does the model make about testung capabilities, changes in vurulence, use of masks, etc ?

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  19. Yea, I'm rabidly into precautions and felt strongly that we need to just wait it out and crush it down until it has very little chance of flaring up again, missing the sunsets for another few months is not asking too much if it will add to our victory....and then the protests ( I am totally supportive of the cause). I've been so devastated that all this effort--closing the schools and leaving all those at-risk kids without anyone looking after them, people losing their businesses, loved ones dying alone in hospitals...have we just completely ruin all the sacrifice? I am so praying you are right, Cliff. It is certainly a robust way of studying outside transmission. But let's wait just another couple weeks and see, we've come this far.

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  20. What percentage of the population was present at these events? Cause if say 90% of the city did not participate, any spike would show at the level of noise, basically. And many were distancing and masked.

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  21. For those who wish to play tennis, courts are now open, as are a number of other activities. See the link for what is now open. https://parkways.seattle.gov/

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  22. Could tear gas and pepper spray be Covid disinfectants?

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  23. Folks pay attention when the prof writes about air quality and particulates when the matter is smoke from forest fires. Why natter when he opines about - ooh, say – how far a virus travels?

    I rather doubt that much if any 'real science' (medical science) went into extending the 6 ft distancing requirement for the outdoors. If there was any “science,” I’d love to see it.

    Just to keep a couple of motors running, “That 6 feet: Upwind or downwind?”


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  24. Check out the metrics for NYC. Over two weeks in to mass protests, and all metrics show the continued decline in new COVID cases: https://forward.ny.gov/covid-19-regional-metrics-dashboard

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