Some think Aaron Ginn’s article that debunks the projections for COVID-19’s rates of transmission, infection, and mortality are off. In an era of big data, from Wall Street to Major League Baseball, occupying the lane alone as the only interpreter of statistics looks a tad risky. But okay, Carl T. Bergstrom can have the numbers (though I wonder if he ever questions the graphs that Stuart A. Thompson creates for the New York Times).
What about the text that Ginn also supplied?
One example is from the Wall Street Journal:
A World Health Organization report on China concluded that cases of Covid-19 in children were “relatively rare and mild.” Among cases in people under age 19, only 2.5% developed severe disease while 0.2% developed critical disease. Among nearly 6,300 Covid-19 cases reported by the Korea Centers for Disease Control & Prevention on March 8, there were no reported deaths in anyone under 30. Only 0.7% of infections were in children under 9 and 4.6% of cases were in those ages 10 to 19 years old
Only 2% of the patients in a review of nearly 45,000 confirmed Covid-19 cases in China were children, and there were no reported deaths in children under 10, according to a study published in JAMA last month. (In contrast, there have been 136 pediatric deaths from influenza in the U.S. this flu season.)
About 8% of cases were in people in their 20s. Those 10 to 19 years old accounted for 1% of cases and those under 10 also accounted for only 1%.
This was not a cherry-picked quotation. Ginn could have added:
Trends in South Korea so far look similar. Among nearly 6,300 Covid-19 cases reported by the Korea Centers for Disease Control & Prevention on March 8, there were no reported deaths in anyone under 30. Only 0.7% of infections were in children under 9 and 4.6% of cases were in those ages 10 to 19 years old.
Ginn also quoted a study from the Center for Disease Control
A growing body of evidence indicates that COVID-19 transmission is facilitated in confined settings; for example, a large cluster (634 confirmed cases) of COVID-19 secondary infections occurred aboard a cruise ship in Japan, representing about one fifth of the persons aboard who were tested for the virus. This finding indicates the high transmissibility of COVID-19 in enclosed spaces.
The larger part of that paragraph includes this.
[H]ospital-based transmission has occurred, potentially affecting healthcare workers, inpatients, and visitors at healthcare facilities, which might explain an increasing trend and the elevated CFR estimates. Indeed, thousands of healthcare workers have succumbed to the disease in China (18), a pattern that resembles past nosocomial outbreaks of Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (19,20). During past MERS outbreaks, inpatients with underlying disease or elderly persons infected in the hospital setting have raised the CFR to values as high as 20% (21,22).
Meanwhile, Ginn brought interpretation of statistics — that would be words — from Nobel laureate and Biophysicist, Michael Levitt. Not shabby, right?
Every coronavirus patient in China infected on average 2.2 people a day — spelling exponential growth that can only lead to disaster. But then it started dropping, and the number of new daily infections is now close to zero.” He compared it to interest rates again: “even if the interest rate keeps dropping, you still make money. The sum you invested does not lessen, it just grows more slowly. When discussing diseases, it frightens people a lot because they keep hearing about new cases every day. But the fact that the infection rate is slowing down means the end of the pandemic is near.”
Turns out Ginn was abstemious in his quotation of Levitt:
There are several reasons for this, according to Levitt. “In exponential growth models, you assume that new people can be infected every day, because you keep meeting new people. But, if you consider your own social circle, you basically meet the same people every day. You can meet new people on public transportation, for example; but even on the bus, after some time most passengers will either be infected or immune.”
Another reason the infection rate has slowed has to do with the physical distance guidelines. “You don’t hug every person you meet on the street now, and you’ll avoid meeting face to face with someone that has a cold, like we did,” Levitt said. “The more you adhere, the more you can keep infection in check. So, under these circumstances, a carrier will only infect 1.5 people every three days and the rate will keep going down.”
Quarantine makes a difference, according to Levitt, but there are other factors at work. “We know China was under almost complete quarantine, people only left home to do crucial shopping and avoided contact with others. In Wuhan, which had the highest number of infection cases in the Hubei province, everyone had a chance of getting infected, but only 3% caught it,” he explained. “Even on the Diamond Princess (the virus-stricken cruise ship), the infection rate did not top 20%.” Based on these statistics, Levitt said, he concluded that many people are just naturally immune to the virus.
The explosion of cases in Italy is worrying, Levitt said, but he estimates it is a result of a higher percentage of elderly people than in China, France, or Spain. “Furthermore, Italian culture is very warm, and Italians have a very rich social life. For these reasons, it is important to keep people apart and prevent sick people from coming into contact with healthy people.”
It doesn’t take epidemiological scientist to think this:
To put things in proportion: “there are years when flu is raging, like in the U.S. in 2017, when there were three times the regular number of mortalities. And still, we did not panic. That is my message: you need to think of corona like a severe flu. It is four to eight times as strong as a common flu, and yet, most people will remain healthy and humanity will survive.”
If Carl Bergstrom wants all non-experts to butt out. Fine. But what newspaper, magazine, or news-website will stand in that great day?