Thursday, June 11, 2020
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.