Friday COVID-19 Briefing


Top news, reports and insights for today:

  1. Daily headline summaries for Friday:
  • CDC faces growing criticism for new testing guidance. Revised recommendations suggest those who have been exposed but show no symptoms may not need to be tested. In my view, new guidance makes no sense and smacks of political influence in CDC policy. (CBS News)
  • A study in India looked at what happened when community health workers started wearing face shields. Before face shields, the rate of COVID-19 infection was 19%. After face shields, no infections were observed. The case for face shields, especially for health care workers as well as barbers, dentists, and others who work in close proximity, is getting stronger (JAMA)
  • A fishing vessel left Seattle in May. When it returned 18 days later, 104 of 122 people on board had been stricken with COVID-19. Why does this matter? A new study used this as a natural experiment yielding the strongest evidence that neutralizing antibodies protected the three people who had them against the SARS-CoV-2 virus (American Society for Microbiology)
  • All eyes are on UNC-Chapel Hill as fall approaches, where 26 new cases were reported among students, bringing the total to over 1,000 since the pandemic began. Campus outbreaks there and elsewhere have thrown a wet blanket over plans to reopen campuses across the nation (The News & Observer)
  • Britain and the U.S. have handled the COVID-19 pandemic worse than other advanced nations, new poll finds (Daily Mail, See Figure A)
Figure A: https://www.dailymail.co.uk/news/article-8673285/Britain-bottom-pile-rankings-governments-handled-Covid-19.html
  1. Decline in U.S. daily cases hits a road bump, deaths lower languidly
    Disease detectives take note: we are accustomed to seeing a jagged and zig-zagged appearance in the daily data. There are several overlapping factors that contribute to that appearance. One is the ebbs and flows of the reporting system (offices close down on the weekend, rush to catch up on Tuesday etc.). Some states, most notably Kansas, only report its new cases every 2nd or 3rd day (what’s up with that Kansas?). The testing labs impose their own noise as supplies run out, machines break down and bottle necks appear and are cleared. Then, of course, there is the natural variation that comes from the epidemic itself. For all these reasons, we learn to squint at the data, trying to see bigger patterns and not be fooled by all the noise. Like so much of science, ours is a constant battle to separate signal from noise. Wheat from chaff.
     On Wednesday, I was seeing a robust signal indicating a decline in daily cases after what looked like a peak in the U.S. around July 18. The last three days of data suggest a slow down in that decline (Figure B). The 7-day average (red line) may be flattening. The data looks more zig-zaggie (to use a technical term) over the last couple of weeks than before. All this makes me want to look at the testing data to see if that helps explain things (see point 3).
     The story with deaths (Figure C) is somewhat brighter. The 7-day average is still dribbling down. Still, there were 1,260 new COVID-19 fatalities reported on Thursday. Week-over-week, deaths are on the rise in Colorado (+33%), Iowa (+19%), Arkansas (+66%), Georgia (+34%), Mississippi (+17%), Virginia (+35%), and Massachussetts (+33%).
     Bottom line: As was the case after the previous peak in April and May, the epidemic curves in this pandemic look atypical. We know what shape those curves should have. Like so much of what we see in this disease, SARS-CoV-2 remains inscrutable. The decline in cases may have hit a bump in the road, while deaths droop further. I suspect both are a function of what is happening in testing (keep reading).
Figure B
Figure C
  1. Testing Update: Is it live or Memorex? U.S. daily testing mirrors cases, passes peak
     I last showed you Figure D on August 11. At that time, the pattern wasn’t clear. As August comes to a close, we see more clearly that testing, like daily cases, has peaked and is on the decline. Hmmmmmm! On August 10, COVID Tracking Project says we peaked at over 900,000 daily tests. In recent days, we are averaging just over 700,000 a day. That decline is proportional to the drop we have seen in cases. As always, if testing is declining, but the TPR is below 5%, we are less concerned. That’s because when the test positivity rate is 5% or lower, it means we are casting a wide enough net to reveal the underlying transmission intensity. Here the orange line has been falling gradually, but still remains significantly above 5%. While the decline from 8.5 to 7.8 is welcome, it does not suggest our testing is efficient enough to warrant a sizable drop in the number of tests we are running.
     At the state level, the variation in testing rates continues to be staggeringly high (Figure E). As I have said before, this is what happens when there is no national policy or leadership. I don’t have the data but I very much doubt that state/provincial variation in testing rates is nearly this high in other nations. Kudos to little Rhode Island! They are kicking butt, having tested 477 of 1,000, nearly half of the state’s population. I was surprised to see Pennsylvania at the bottom, testing only 13 of 100. Louisiana and Tennessee are the two states in the South that are testing near the top of the rankings, six other southern states are below the U.S. median.
     The bottom line: If you are following the news, you know the White House and the CDC are under severe criticism for the recent release of guidelines that appear to throw a wet blanket on testing. Is that guidance motivated by science and by a desire to improve America’s pandemic response, or is it motivated by politics and a desire to make the numbers look more favorable to the administration as the election inches closer? You, dear reader decide for yourself. I bet you can guess what my answer is.
Figure D
Figure E
  1. Quirky Qorner: Why isn’t contact tracing working well? Look to strip clubs for an answer
     The Toronto Star reports that public health officials this week said are talking about conduct contact tracing in a prominent strip club in that city. Surprisingly, they found that two-thirds of visitors provided false or incomplete contact information when approached. While provincial infection rates have dropped in Ontario, the stage was set for contact tracing to help keep the outbreak at bay. Contact tracing is only as good as the information people provide about their social network interactions and patterns. While strip club patrons may seem like a special case, trends across the nations point to a wide-spread reluctance on the part of citizens to trust public health authorities. Few users are downloading and using phone-based tracking apps. As Figure A shows, Canadians generally like how their government has handled coronavirus, so we won’t be surprised to learn that American’s are even more wary about giving authorities personal information on their social connections.
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