COVID-19 was at first believed to be a public health threat on par with SARS, with a mortality rate around 10%. Since then, better data has shown that it has much lower case mortality, comparable to the case mortality of ordinary pneumonia (which is about 1.4%, see here and here). It is a threat only to the elderly and those with pre-existing health problems, again like ordinary pneumonia. Bizarrely, the world’s politicians, public health officials, journalists, and other opinion leaders have instead decided to escalate their reaction, as though unaware of the change in factual reality, or unwilling to admit error.
The most striking thing about the cycle of one-upmanship in overreaction is that the solution is always to curtail freedom. If people are willing to renounce their freedoms over small risks, how easily will governments be able to curtail freedom when there is a more serious threat. As with the exploitation of 9/11, this objective is attained by promoting excessive fear, which short-circuits reasoning even among the educated.
There are two types of factual distortions when making these faulty risk assessments. First, the risk of the new threat is overestimated. Second, already existing risks are underestimated or ignored altogether. These errors combined to create a gross overestimate of marginal risk.
According to a study of 1099 Chinese patients, published in the New England Journal of Medicine, the mortality of COVID-19 is 1.4% of those who test positive. Since at least as many others are asymptomatic and never tested, true mortality is likely 0.5% to 0.8%.
The increased risk of death is mortality times prevalence. In China, prevalence is 1 in 15,000. In Italy it’s 1 in 5000. In the USA it’s 1 in 200,000. In all these nations, the risk of death is less than or equal to dying in a car accident. So driving a car instead of taking public transit to avoid COVID-19 may actually increase your risk of death. In any event the marginal risk, positive or negative, is miniscule. Someone genuinely worried about this level of risk should avoid driving or riding in an automobile.
Suppose that containment fails, as seems likely, and further that this new strain becomes as prevalent as other forms of flu, so that COVID-19 should have about 2% prevalence, i.e. 1/5 of flu cases (10% prevalence). The increased risk of death, compared with average flu mortality of 0.1%, would be 1/50 * 1/200 = 1/10,000. Here I assume mortality of 0.6% for COVID-19 vs 0.1% for average flu. This is to compare apples to apples, since the flu figures include (estimated) unreported cases. Most sites get this wrong, and compare the flu figures for all cases against the COVID-19 figures for positively-tested patients only.
This figure of 1 in 10,000 is likely overstated, since it excludes consideration that many of the “excess deaths” are in people with preexisting conditions who would have died of something else shortly. This pessimist scenario, in a nation of 300 million, would result in 30,000 excess deaths.
Preventing such a scenario is certainly worthy of strenuous measures, but not without limit. One must also consider the effectiveness of such measures, and the cost in terms of public health. Sinking the economy and depriving people of months of income may cause comparable excess deaths, especially if people are prevented from getting cancer screenings as some health systems are recommending. 30,000 excess deaths represents a 50%-60% increase in annual flu deaths, but there are other bigger killers, both those existing, and those we may create by excessive reaction to this new public health risk. A simplistic attitude that “no measure is too big” fails to be a rational form of risk management.
At some point, we may have to grapple with the possibility that containment does not work. The USA may not have the same legal means at its disposal to compel quarantine that may exist in the more centralized authority of Italy or China. Also working against containment is the low mortality rate, the possibility of carrying the virus in mildly symptomatic and asymptomatic individuals, and the unusually long incubation period. Indeed, once the virus proliferates beyond a certain threshold, containment of COVID-19 would seem to be as impracticable as containing the common cold or the flu. While we may not have reached that point yet, we must recognize the possibility that at some point continued efforts at containment are not worth the cost, simply because of their low probability of success.
The reactions have been so rapid, and so outpace the actual facts on the ground, even when the number of cases is statistically negligible, that we cannot consider them to represent the result of careful deliberation. Rather, as in the closure of multiple universities on the same day, it is more like the imitative behavior of a panicked and stampeding herd. In such a climate, it may take more courage to do less than to do more. It is very easy to say that money is no object and leave the private sector to pay for government largesse. Those of us who have to make budgets and do not have the power to print money may have a different perspective. This is not a mere economic problem, for it can swiftly transform into a humanitarian catastrophe at least as great as the one ostensibly being prevented.
Update: 28 March 2020
Misinformation continues to spread. First, there is the oft-repeated claim that, absent our draconian containment measures, the virus would spread to 60% of the population, resulting in millions of deaths in the US. This is a cumulative figure over two or three seasons, ignoring the near-certain fact that pharmaceutical measures and natural antibodies will reduce the virulence of the disease by next season. It is effectively an impossible scenario, and again is not comparing apples to apples, as the seasonal flu death figure is annual.
Second, the mortality rate continues to be overstated. As testing becomes limited only to those who are hospitalized, the “mortality rate” of tested positives will increase, since you are actually measuring only the most severely affected subset of cases. Worse, in Italy, anyone who dies with coronavirus is counted as a death due to COVID-19, although 99% of fatal cases had comorbid conditions. The best data from South Korea, which has far more aggressive testing, currently points to a mortality rate of 0.7%. Using this figure as an upper bound and applying the more exact population of 327 million for the US yields a “pessimist” scenario of 39,000 excess deaths this season. We may get there anyway as outright containment has proven ineffective, and we are now hoping only for mitigation, i.e., slowing the spread.