COVID-19 Exponential Growth vs Hospital Capacity
Modeling the pandemic to spur mitigation measures

In this post, we explain how models of COVID-19 exponential growth vs hospital capacity have sparked unprecedented mitigation strategies and tactics. These are to prevent overwhelming hospitals and ICUs in countries, states and cities. In the following post, we describe those mitigation strategies.

History of pandemic responses

This image depicts Baccacio’s Decameron, a 14th C. novel about a group of Florentines who flee to a rural villa during the Black Plague and tell stories to pass the time.
Baccacio’s Decameron is a 14th C. novel about a group of Florentines who flee to a rural villa during the Black Plague and tell stories to pass the time.

Past strategies to cope with pandemics were even cruder than what we are doing now! People had two choices: run away or turn away sick people. Many people fled plague-ridden cities (often carrying disease with them). Even today, many people have fled New York City and other urban centers of the COVID-19 outbreak.

Other historical tactics included closing seaports and turning away ships with infected people on board. Or quarantining neighborhoods, as San Francisco did with Chinatown during the plague of 1900. Today, that means quarantining cruise ships, canceling flights, closing borders, and restricting domestic travel.

Vaccination for smallpox in the 18th C. was a game-changer. But without knowing why it worked, devising vaccines for other diseases was impossible. During the 17-19Cs, physicians and public health authorities used quarantine of ill people to stop transmission.

Germ Disease Theory led scientists and understand of what causes infections: small, invisible-to-the-eye microbes and viruses are responsible for exponential growth.

In the last half of the 19th C., the germ theory of disease gave medical science a new understanding of what caused infections. Discovering microbes (and later, smaller entities we now call viruses) made it easier to understand how they spread. This spurred advances in cleaning up water and removing garbage. It also created new sciences: microbiology and immunology. These form the foundation for modern infectious disease research and ultimately, biotechnology.

20th C. pandemic response tool kits

The availability of antibiotics dramatically reduced the spread of bacterial pandemics in the 20th C.  Even more, widespread vaccination (including for flu) has greatly reduced the burden of bacterial and viral diseases. However, we currently have no proven treatments effective against SARS-CoV-2 (although several are in emergency testing). Furthermore, we are at least 18 months away from a vaccine.

Our medical response is limited to advanced high-tech nursing. This is basically keeping people with serious COVID-19 cases alive until their beleaguered immune systems do the rest. Thus, hospitals’ ability to care for victims is essential to keeping the death rate low. In most countries, however, there are not enough hospital beds and intensive care capacity to meet the expected surge of coronavirus patients. We are in a race to keep the exponential growth from overwhelming hospital capacity.

Slowing COVID-19 exponential growth to relieve hospital capacity

Wear a mask in public to slow COVID-19 exponential growth

Worldwide, we are trying (somewhat) simultaneous, (somewhat) coordinated measures to break chains of transmission. Governments have instituted stay-at-home orders unevenly and usually later than ideal. Case identification, tracing, and quarantine (containment) only work early in an outbreak, but these measures are being implemented a little later than they should. 

China’s weeks-long delay applying containment measures contributed to the worldwide spread of the pandemic. But Singapore, South Korea, and Taiwan used these tactics early (plus masks) to significantly contain their outbreaks. In contrast, the United States was slow to react. If Seattle’s Patient Zero had been quarantined upon his return from Wuhan rather than allowed to roam about for four days, lives could have been saved and the outbreak contained in Washington State. 

Once it’s too late for containment, alternative strategies must focus on mitigation. These include closing borders, canceling travel, voluntary isolation, and mandated lockdowns. Many individuals and companies went virtual in February to increase distancing. This was especially true in Silicon Valley, where working from home has broader acceptance and better infrastructure.

The downside to lockdowns

Our global, just-in-time economy is particularly fragile amid a worldwide shutdown. Most large businesses are dependent upon global supply chains. The United States has outsourced most of its manufacturing and computer programming. Many industries use lean manufacturing or warehousing practices (just-in-time) and are now facing shortages of materials. Grocery stores used to keep months of inventory warehoused, but now keep only days. Grocers Stopped Stockpiling Food. Then Came Coronavirus. That’s why you couldn’t find toilet paper! 

Under zero-interest-rate policies and prolonged stock market bubbles, many corporations invested in stock buybacks and M&A rather than infrastructure or buffers against disaster. So, many employees are being laid off or furloughed without pay. Consultants, contractors, freelancers and gig workers are losing projects and clients. Small businesses in “non-essential” categories may go bankrupt. Tenants cannot pay rent. Landlords have lost income.

Many people are already suffering because of isolation and lockdowns. People with autoimmune conditions are anxious. Many of them isolated themselves before mandates came down. Healthcare systems are under enormous stress. Pharmaceuticals and medical supplies are particularly vulnerable, since many essential ingredients are only manufactured in China. Many younger healthcare workers have never had to face an infectious pandemic. There are limited stockpiles of medical equipment and supplies. California once had mobile hospitals and a ventilator stockpile. But it dismantled them.

Why we are taking such drastic measures

Back in 1918, medical workers and the military commandeered gymnasiums and put up tents filled with cots of people who received the most basic nursing care. No intensive care technologies (oxygen, respirators, etc.) were available at the time. So, many people simply died of pneumonia (imagine drowning from the inside out). Things were not much different during the flu pandemics of 1957 and 1968. Political leaders, the news media, and voters all knew that many people would die. For most of human history, enduring a plague was about luck, loss and grief. 

Since then, we have built a high-tech health system capable of sustaining the lives of many more people. Under conditions considered normal only 50 years ago, many of us would already be dead. Therefore, we have a larger population than ever with risk factors for poor COVID-19 outcomes. In the United States alone, there are 37 million people older than 65. There are more than 70 million Americans with high blood pressure. A further 30-40 million live with chronic diseases, including 15 million people with autoimmune conditions. Some 37 million are obese. And these people vote. 

A COVID-19 exponential growth curves detailing possible death count

On Tuesday, March 31, Drs Fauci and Birk presented a chart that suggested in a best case scenario, 100,000 Americans could die. The White House press corps was shocked.

With exponential growth and long hospital stays (2-15 days in ICU) an uncontrolled pandemic will rapidly overwhelm hospitals, especially ICU capacity and staff. The Imperial College Model makes this case most vigorously. If we do nothing, hospitals will be unable to care for thousands of people, and death rates will soar faster. We have seen this in Iran and Italy and may be seeing soon in Spain and New York.

 Imperial College Model for COVID-19’s potential impact on US ICU bed capacity.
 Imperial College Model for COVID-19’s potential impact on US ICU bed capacity.

The silver lining

Hopefully, these drastic measures will flatten the curve from exponential. California is seeing fewer cases and deaths than expected, possibly because of early actions by some polities (Santa Clara County, home of Stanford University) private companies (Facebook and Salesforce went virtual in February) and individuals (some started isolating at the beginning of March). Early interventions, however unsystematic, may have more impact than carefully thought through later ones.

The next post will describe some of  the mitigation tactics being pursued around the world.

Stay well!

Written by: Bonnie Feldman, DDS, MBA, Ellen M. MartinAnnie Rooker

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Let us know your thoughts!

The COVID-19 pandemic is a rapidly moving situation. Therefore, it’s hard to keep up with the tsunami of information, misinformation, and disinformation. Moreover, there’s high noise-to-signal ratio, especially on social media. Let us know in the comments if you have good sources to share or if you spot incorrect or outdated information in our posts. Also, let us know if you have questions or more topics you’d like us to tackle.

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