Top news, reports and insights for today:
- A tale of 5 Thursdays: what non-linear change looks like
There were almost 29,000 new cases added yesterday. Quick, try to remember how many there were last week. One theme of my blog has been learning to think in terms of exponential change. It’s something we aren’t used to and it takes practice. It’s also vital for understanding epidemics. The figure below shows the epidemic curve for U.S. cases since March 1. This is the same figure I show every day or two. The difference here is that I have highlighted one week changes over the past 5 Thursdays. How many cases last Thursday? Answer: just over half as many (17K). Two weeks ago? Four thousand. The week before that? Four hundred. The week before that? 64. Since March 5, less than a month ago, we went from 64 new cases to 29,000, a 450-fold increase. Since that Thursday, new cases increased 6-fold, then 10-fold, then 4.3-fold, 1.8-fold.
What does it mean? It is tempting to think that the rate of growth in new cases is slowing, that social distancing may be flattening the curve. That may partly be true. However, as I have said before, it’s also possible that we are seeing a flattening in testing capacity. Where will we be four Thursdays from now?
- U.S. adds record-breaking 1,075 deaths, passing 6,000
Thursday saw a 23% rise in deaths continuing a pace of doubling every three days. Just two weeks ago, just 55 deaths were reported. States with noteworthy rises include Nevada (+45%), Florida (+42%), North Carolina (57%), Connecticut (+32%), and New Jersey, where numbers doubled in one day with 182 new deaths. New York continues to lead the nation with 2,373 deaths. The Wall Street Journal reports that the City’s crematory operators are handling triple the number of bodies as rules are suspended allowing them to operate around-the-clock. However, the fraction of all U.S. deaths in New York continues to fall slowly (now at 41%) as the pace of outbreaks accelerate in states like New Jersey, Connecticut, Massachussetts, Michigan and North Carolina. The U.S. now ranks third behind Italy (>13,000) and Spain (>10,000) with a combined total of over 6,000 COVID-19 fatalities.
- Concerns rise about possible airborne transmission, wider use of masks now under consideration
Elizabeth Cohen of CNN reports yesterday that a prestigious panel of scientific experts told the White House that transmission of the virus that causes COVID-19 might be occurring through airborne routes. It had been believed that the main route of transmission was through respiratory droplets from coughs and sneezes that land of surfaces and are picked up through touch. That still may be the main way the virus spreads. However, the expert panel said that new findings “are consistent with aerosolization of virus from normal breathing“.
What does this mean? While this question remains hotly debated, it is increasingly apparent that consideration must be given to the possibility that the virus can remain airborne and enter the body directly. This has important implications for both the general public and for health workers. Recommendations about the use of masks and respirators are now in flux. The President has indicated that new guidance on masks will be released soon. Wearing masks is still about preventing the spread of the disease to those who don’t have it. Paper or cloth masks are still likely not effective for keeping the virus out, especially if airborne transmission is confirmed.
Thomas A. Glass, Ph.D. 