First, it seems that the Wuhan virus has peaked in the U.S. This chart is from the CDC web site. It shows cases of COVID-19 by date of onset. I have posted it a couple of times before, with the caveat that this chart only included around one-quarter of the total number of confirmed cases. Now, however, it includes more than half of cases recorded by the CDC. I assume that no date of onset is available for the others. At this point, it seems clear that the epidemic has assumed the bell-shaped curve predicted by Farr’s Law in the 19th Century:
It should be noted that deaths haven’t necessarily peaked, as deaths follow onset by several weeks, on average–which is one of the reasons why relatively low fatality totals so far cannot be attributed to governments’ shutdown orders.
Second, there is growing evidence that many more Americans have had COVID-19 than has generally been thought. Reuters reports that of the sailors on board the COVID-stricken aircraft carrier Theodore Roosevelt, 60% of those who tested positive for the virus were asymptomatic. This is a higher percentage than was previously estimated by Dr. Fauci, 25%-50%. The Reuters reporter doesn’t seem to understand that this is good news, for two reasons.
First, it means that the fatality rate for COVID-19 is lower than most have believed. I think the balance of evidence so far is that the Wuhan virus is somewhat more lethal than the usual seasonal flu, but of the same order of magnitude. It is possible, however, that it may prove to be no worse, statistically, than the average flu.
Second, it means that the U.S. is closer to achieving herd immunity than previously believed. This ABC News story is to the same effect:
The first large-scale community test of 3,300 people in Santa Clara County found that 2.5 to 4.2% of those tested were positive for antibodies — a number suggesting a far higher past infection rate than the official count.
That’s the good news. The bad news is that we are still a long way from the levels that confer herd immunity.
Next, IHME updated its model today. The new projection is more optimistic, with 60,308 U.S. COVID deaths. That is a positive, although I don’t think the IHME model is any more reliable than any of the others. More good news for those who (like me) live in Minnesota: IHME has lowered its fatality projection for our state from 656 to 195. How’s that for progress? Given that the prior projection was all of four days old, this kind of radical revision obviously does not create confidence in the model. But the new prediction is undoubtedly more accurate than the old one.
Other states I have been following fare well, too. A week ago, IHME projected South Dakota to have 356 coronavirus deaths. Four days ago, IHME reduced that prediction to 181. Today, it dropped to 94. So IHME is slowly coming closer to reality. I believe that South Dakota currently has seven Wuhan flu deaths.
Weirdly, IHME thinks things have gotten worse in North Dakota. A week ago, their model showed N.D. with 369 deaths, a ridiculous number. Three days later, the projection dropped by 91%, to 32. Now–just four days after that model revision–IHME has moved North Dakota back up to 149 deaths. None of this bouncing around has much to do with reality; as of yesterday, IHME showed North Dakota with just 9 deaths. The more closely one looks at the IHME model over time, the less likely one is to give it much credence.
As part of today’s update, IHME has, for the first time, released a state-by-state analysis of when shutdown restrictions might be eased. I have not had time to study it in detail, and have no confidence in it. I may comment on it at a future date.
Finally, this is a good time to update the simple bar chart I have published several times before. It shows, from left to right: the average annual number of fatalities caused, worldwide, by seasonal flu viruses, per the World Health Organization; the global number of COVID-19 deaths, to date; the number of deaths caused by the seasonal flu virus in the U.S. just two years ago, 2017-18, according to the Centers for Disease Control, and the number of COVID-19 deaths in the U.S. so far, per the same organization:
Currently, global COVID deaths are just under 30% of the average for a seasonal flu bug, per the WHO. Those numbers are likely wrong, because China and Iran have almost certainly underreported their fatalities. If we assume that China’s true fatality number is ten times what it tells the WHO, and Iran’s is three times, then total global fatalities from COVID-19 would be 41% of an average flu season, so far.
For the U.S., according to CDC, the COVID-19 deaths to date equal 53% of the deaths from seasonal flu two yeas ago.
COVID-19 is a disease, and there nothing good to be said about diseases. But today’s news is generally positive.