Daily COVID-19 Briefing: 4/23/20

Top news, reports and insights for today:

  1. Deaths and new cases remain flat. Reopening states Georgia, South Carolina, Florida, Tennessee, all saw 30% rise in new cases last week
    On Wednesday, 29,743 new COVID-19 cases were reported, a 4% rise in the cumulative total. Another 2,146 American’s lost their lives to the virus, a 5% rise in the total death toll. Trend lines based on 7-day moving averages show that both deaths and new cases are flat (Graphs 1 and 2). Seven states matched or set new daily high deaths including Arizona (21), Minnesota (19), Missouri (19), Alabama (52), Washington DC (15), Massachussetts (221), and New Hampshire (6). Regionally (Graphs 3 and 4), cases are surging in the Midwest, with greater than 50% 7-day growth seen in Iowa, Minnesota, North Dakota, Nebraska, Ohio, and South Dakota. New case hot spots also seen in the South (Mississippi, and Virginia) and the Northeast (District of Columbia, Delaware, Maryland and Rhode Island). However, as deaths lag behind cases, the mortality hot spots differ, including Minnesota, Alabama, North Carolina, Virginia, West Virginia, Connecticut, Massachussetts, Pennsylvania and Rhode Island. It is possible that deaths will rise next week in midwestern states after rising cases this week. Several states move to reopen businesses according to a report in the Washington Post including Georgia, South Carolina, Florida and Tennessee. All four of these states have seen 30% jumps in new cases over the last week (Graph 3). Deaths rose over 50% last week in Florida and Georgia and by a third in South Carolina and Tennessee. Experts are unified in the belief that the reopening of these states will lead to sharp increases in cases and deaths.
  1. A sharper picture of prevalence and CFR begins to take shape
    The big news today, covered in today’s Top Pick, is the release of results of a seroprevalence study of 3,000 people in New York. The results, while preliminary, can now be added to the growing number of studies trying to get to a better estimate of the total fraction of the population infected and what the true case fatality rate is. I have repeatedly emphasized how vital these two pieces of information are. I have also stressed that all studies have limitations and that no single study can answer big questions alone. Instead, as disease detectives, our strategy is to triangulate across studies, considering the strengths and weaknesses of each, paying close attention to the overall patterns. So, let’s look at the studies that have so far come on to our radar screen (see table below). There are more studies than this, but let’s keep it simple. The top row of this table is the new study today in New York. It suggests that 14% of New Yorkers may have been infected, which means as many as 2.7 million cases, a 10-fold higher number than current testing now suggests (257,000+). The New York prevalence is quite similar to the much earlier German study. New York estimates a CFR of 0.5%, five times higher than seasonal flu and higher than the rest of the estimates. The two California studies estimate a prevalence of 3-4%, which is dramatically lower than New York.
    What this means? We need to squint at this table. All these studies have limitations. We don’t focus on any one study, but instead look for patterns. Overall, these studies are telling us that the prevalence of COVID-19 infection is orders of magnitude greater than current testing indicates, somewhere between 10 and 50 times higher. It also says the CFR is in the neighborhood of 0.2% and 0.5%. This number is thankfully well below the crude death ratios suggest, but indicate that COVID-19 will take substantially more lives than seasonal flu.

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