COVID-19 isn’t just another flu

In psychology, there is an established effect known as normalcy bias. Human beings tend to believe that the world will operate as their experience tells them it will. This phenomenon can be evidenced right now in popular culture by the oft-repeated phrases, “It can’t happen here, it will be different” or “the vast majority of cases are mild, it’s similar to the flu.” It has been more than a century since a large-scale pandemic threatened the lives, prosperity, and fortunes of the global population in a real way. The last few decades have seen several potential global pandemics fizzle out or end up far less severe than portrayed by media and government entities (SARS, H1N1, Ebola). We have an innate tendency to assume that this, too, will be the same.

Unfortunately, this bias ignores the vast majority of human history and what we currently know about COVID-19. Historically speaking, both epidemics and pandemics have swept through human populations with frightening regularity and speed. Cholera, Tuberculosis, and plague regularly circulated through medieval communities killing and maiming large percentages of the population. The Antonine Plague, The Plague of Justinian, and the Plague of Athens all wiped out vast swaths of ancient urban communities. Even in the past 700 years, we have dealt with cholera, yellow fever, and of course, the Black Death, which reduced Europe’s population by half. The advent of modern medicine, antibiotics, and vaccinations have produced an era of global health and wealth unprecedented in human history. At the same time, it has had the unintended effect of inoculating us against the threat that epidemics pose to human life in a highly interconnected world.

“One citizen avoided another, hardly any neighbour troubled about others, relatives never or hardly ever visited each other. Moreover, such terror was struck into the hearts of men and women by this calamity, that brother abandoned brother, and the uncle his nephew, and the sister her brother, and very often the wife her husband. What is even worse and nearly incredible is that fathers and mothers refused to see and tend their children, as if they had not been theirs..”- Giovanni Boccaccio writing on the effects of Plague in Florence, The Decameron vol. I

Epidemics were a fact of life for ancient and medieval peoples rather than an aberration. The past century is different precisely due to the lack of substantial outbreaks rather than their presence. The last significant mortality occurred in 1918–1919 as the Spanish Flu swept through Europe and the United States, killing millions and leaving its mark on an entire generation of young men and women. Epidemic disease on a massive scale does not exist in the living memory of people in Western Europe and the United States. Our lived experience has taught us that the media cries wolf far more often on novel pathogens than is warranted and so far hasn’t been right once. Unfortunately, this does not appear to be the case for COVID-19.

COVID-19 is Different

The first lesson taught in any public health class is not to cause panic. Panic exacerbates the social disorder caused by a pathogen while adding strain on healthcare systems and increasing spread. Thousands will rush to get tested and crowd stores, creating the prime conditions for disease to propagate. Social disorder does nothing but aid and abet already virulent diseases as they work their way through the population. All one has to do is look at the crowded halls in Wuhan hospitals during the early phases of the outbreak to understand how panic worsens problems.

Therefore, the tendency is to downplay and deflect. In the United States, many observers are aware of media and government entities repeatedly comparing COVID-19 to the flu in a positive light. This was on full display last week at President Trump’s press conference.

“You know in many cases when you catch this it is very light — you don’t even know there’s a problem. Sometimes they just get the sniffles, sometimes they just get something where they are not feeling quite right and sometimes they feel really bad but that’s a little bit like the flu. It’s a little like the regular flu that we have flu shots for and we will essentially have a flu shot for this in a fairly quick manner.”

This approach engenders complacency. Very few people will spend significant amounts of time researching the flu’s mortality rate (around .1% of 1/1,000) or fact-checking government claims. People then fail to take necessary precautions such as washing hands, avoiding large social gatherings, and avoiding travel to areas that are high risk. Why cancel a $1000 plane ticket to prevent a flu-like illness?

Another common objection is that there are currently only a few thousand cases. Exponential growth is not an intuitive concept for human beings. In 1918, the Spanish flu began with a cluster of cases in rural Kansas and, within 768 days, spread to over 500,000,000 people, killing tens of millions. The Australian Medical Association currently estimates that COVID-19 cases double every 6–8 days. If we take an average of 7 days for a doubling of cases and assume a current case count in the U.S. of 1,000 (not an improbable assumption) by April 29, 512,000 people will be infected with COVID-19. By May 27, that number is 8,192,000. Unfortunately, many experts believe that the virus is no longer containable; the most we can do is try to mitigate growth and buy time for a vaccine.

(Please note that I am not predicting these numbers, mitigation efforts will certainly slow the spread, merely providing an example of exponential growth)

Just how dangerous is COVID-19? Lessons from China

On January 23, China enacted the most extensive quarantine in human history. Eleven million people were barred from leaving the city of Wuhan. Over the coming weeks, the CCP extended quarantine measures to the entire Hubei province, covering over 60,000,000 people while also enforcing additional precautions across most of mainland China. Over the past two weeks, the draconian measures China implemented in early February have shown substantial results in slowing the spread of disease. It appears as of now that mitigation in China has worked, and we have learned a great deal about COIVID-19 since it came to the attention of the Chinese health authorities in late December. According to the most recent estimates from Mike Famulare at the Institute for Disease Modeling and the Chinese CDC, we have reason to believe the following:

Case Fatality Rate is estimated to be .94% (.37%–2.9% with a 95% CI)

R0 (Number of people each case spreads to) is estimated to be 2.4–2.9 prior to mitigation efforts in Wuhan (this metric is highly context dependent)

The Average time from first symptoms to death is estimated to be 18 days.

Incubation Period average of 5.4 days

Asymptomatic Transmission

“…evidence to date points toward 2019-nCoV having the potential have comparable severity to the 1918 flu pandemic in the absence of effective control and treatment, when averaged across all ages.”- Mike Famulare, Institue for Disease Modeling

In understanding the overall fatality rate of COVID-19, however, we must take into account a second element. Namely that many cases require treatment in an intensive care unit, and there aren’t enough hospital beds in most countries to support a massive influx of patients. We can see this clearly in Hubei, where the CFR currently stands at over seven times that of other cities in China (7.2% versus less than 1% for the rest of the country).

Overwhelmed Healthcare System: As the disease spread exponentially in Wuhan, the medical system quickly became overwhelmed. Due to an average incubation period of between 4 and 6 days, an average of one week before critical illness after symptom onset, and the occurrence of “super-spreaders,” hospitals can become overwhelmed within a brief period. As the exponential growth curve in Wuhan accelerated, hospitals rapidly became overwhelmed with critical patients. This run-on hospitals likely resulted in a vastly higher CFR than the rest of mainland China. We know from the Chinese CDC’s retrospective study on over 70,000 cases that roughly 19% of cases are classified as severe or critical. Many of these cases likely result in fatality without medical intervention.

Image of a crowded Wuhan Hospital during the height of the epidemic

Key Takeaways

If we are to take Chinese data at face-value or close to it, we can draw two principal conclusions:

First, COVID-19 is a very severe illness for which a large percentage of patients need supportive medical care to survive (somewhere between 5%–10%). We also know that the Case Fatality Rate will be highly context-dependent, in a standard healthcare setting with adequate capacity, CFR will likely range between 1–2%. However, in a situation in which exponential growth is allowed to continue, unabated CFR may increase substantially due to the lack of available healthcare resources for a sick population.

(Please note that the above chart represents confirmed cases. It is likely that there were several thousand in Wuhan on January 22 when testing began)

Secondly, social distancing measures must be implemented early to flatten the exponential growth curve. Due to the delayed onset of severe symptoms and the incubation period of COVID-19, a hospital system can go from full-capacity to completely overwhelmed in a matter of 2–3 weeks. Wuhan shows us in the most visceral way possible what happens when mitigation strategies aren’t implemented early. The incubation period of 4–6 days when combined with exponential growth and a lag-time between the onset of symptoms and onset of severe symptoms creates a dangerous circumstance in which (in the absence of testing) health authorities only become aware of an outbreak when growth is already ramping up rapidly.

It can’t happen here: COVID-19 and the U.S.

So far, the United States’ response has been less than heartening. Although testing finally appears to be ramping up, it may be too late to allow for the public health knowledge needed to institute mitigation measures effectively. It is impossible to implement effective mitigation tactics without first understanding the scope of the problem. We know that COVID-19 infections double every 5–7 days without mitigation efforts. Three weeks ago, Italy and South Korea reported cases in the double digits and deaths in the single digits. As of this writing, Italy has 3089 confirmed cases with 107 fatalities, and South Korea has 5,766 cases with 35 confirmed fatalities.

We also know that due to incubation periods, whenever a mitigation measure is imposed, we can likely expect another near doubling from current levels in symptomatic cases before mitigation begins to alleviate the situation. Unfortunately, due to a profound lack of tests in the U.S. (Below 1,000 tests as of this writing), we have a minimal idea to what extent it has spread or may be spreading across the country. The limited picture we can paint is bleak. Community spread of COVID-19 is currently confirmed to be occurring in California, New York, Washington State, and Oregon, and so far, the disease has claimed 11 lives.

The United States also has intrinsic factors related to its healthcare system and economy that make a disease like COVID-19 very difficult to control. Tens of millions of American’s lack health insurance, which causes widespread aversion to seeking medical care. Secondly, since 27% of Americans lack paid sick leave, many will be forced to choose between showing up to work sick or losing their income if they fall ill. Often these workers will be in the industries which are most likely to spread illness (food service, retail, and other service industries.) These structural elements will likely worsen an already bad situation as COVID-19 continues to spread.

“Disruption to everyday life may be severe”- Doctor Nancy Messonnier, Director of CDC National Center for Immunization and Respiratory Diseases

At present, community spread within the United States appears to be limited. Only four states have confirmed community transmission, although many have imported cases from other countries. This is unlikely to be the case for very long. As flights continue to East Asia and Continental Europe, community outbreaks across all major U.S. population centers become inevitable. Without serious efforts to mitigate the spread, including banning large gatherings, closing schools, encouraging telecommuting, and imposing mandatory quarantines on the sick, we risk allowing what will be a disaster to become a tragedy of unprecedented proportions in the 21st century. We can learn from Wuhan; the sooner these measures are implemented, the more we can control the course of the epidemic.

By ignoring the lessons from Wuhan and the lessons from the multitude of epidemics which litter history, we edge closer to catastrophe. Thousands of outbreaks have swept through communities from Ancient Rome to the Byzantium Empire, Medieval Europe, and Ancient China, every one a human tragedy. Modern medicine has revolutionized the world, but to think that we are immune from a modern plague is foolhardy at best and dangerous at worst. It can happen now, and it can happen here. Sometimes the wolf really is there.

Originally posted on https://www.tersum.net