By Edison Liu and Jill Goldthwait
Previously, we explored why social distancing at the personal and population level is critical in pandemic control, and the science behind the recommendations. Now, we will discuss how we would use these principles to deal with the expected surge of cases in the coming weeks, and what we need to do in its aftermath.
What is the difference between an epidemic and a pandemic? It’s all about scale. An epidemic is a disease that spreads across a community or region; in a pandemic the disease engulfs an entire nation or the whole world. In infectious diseases, epidemics emerge and then go away, sometimes even eradicated. In Zika, Ebola, SARS and MERS, all efforts were to contain and extinguish these epidemics. Pandemics are very difficult to snuff out except by extraordinary means – either by massive deaths that reduce the number of viable hosts for the pathogen, or by herd immunity through vaccination such as what happened with smallpox. This is why draconian efforts like mass cullings of chickens were made to extinguish the H5N1 bird flu – to prevent the virus from establishing itself in human populations as a pandemic.
SARS and COVID-19 are both coronaviruses. In the case of SARS, governments were able to contain and eliminate SARS through vigorous interventions such as the test, treat and track strategies we discussed previously. But COVID-19 is much more infectious and because of delays in governmental response, it is now a pandemic.
In the absence of natural immunity or human intervention, an epidemic or pandemic spreads in a characteristic manner. The pattern is exponential growth in which the rate of expansion increases over time. At the beginning of the COVID-19 epidemic, the number of new cases appeared to increase slowly day by day. But this rate picked up dramatically such that the number of new cases in the United States is now doubling every three to four days. This rate of doubling will continue until the virus runs out of people to infect because most individuals will have achieved immunity to the virus, or most individuals are either physically isolated (by social distancing) or dead, thus depriving the virus of any hosts to infect. These trends follow mathematical formulas allowing epidemiologists to project the spread of an epidemic, and the effects of social distancing/shelter-in-place mandates.
If social distancing orders are followed, the exponential rise in COVID-19 cases will be blunted and hopefully suppressed. This will “flatten” the curve and then cause the rates to decline. On a graph, this resembles a hill with a rising slope, a peak and a falling slope. It is estimated that the peak of new COVD-19 cases in the U.S. will be in mid-April with the estimated high for Maine around the week of April 26 (https://covid19.healthdata.org/projections). This peak will be accompanied by a spike in hospital utilization and, unfortunately, by a surge in COVID-19 related deaths. If the current trends continue it is projected that as many as 81,000 Americans may die of COVID-19 by the end of this surge (http://www.healthdata.org/research-article/forecasting-covid-19-impact-hospital-bed-days-icu-days-ventilator-days-and-deaths).
These deaths are tragic, but an equally disturbing outcome is that entire medical systems will be overloaded and healthcare workers decimated. In Italy, over 40 doctors have died of COVID-19 within a short time, and at least 6,200 medical workers have been infected representing around eight percent of the total infected in Italy at that time. The double whammy of a surge of critically ill patients and a reduction in healthcare workers has put Italy in a monumental medical crisis.
Independent to the death toll of the COVID-19 pandemic, there will inevitably be increased deaths from patients with other diseases who cannot receive care. Combined with the untimely deaths of healthcare workers, our medical capacity nationwide will continue to diminish in the post-pandemic period.
For hurricanes or major storms, we can project their strength and paths from mathematical and computer models. From our scientific and historical experience, we know what kind of damage can be inflicted and therefore, we prepare. We batten down the hatches, establish sanctuary sites and even evacuate areas. Rational people would not deny the coming of the storm and go out to party. This COVID-19 pandemic is no different – we need to be ready.
How can we be prepared? First, we must maintain strict social distancing measures. Recall from our previous discussions that the more frequent a virus is in a population, the more stringent the restrictions against social gatherings must be because in a surge, the likelihood of randomly encountering someone who is infected is higher. Though there are no cases in Hancock County yet, there will be. Despite recommendations that people in states with high caseloads stay at home, these individuals are traveling and Mount Desert Island is a popular destination. This travel in the coming months may prolong the presence of disease here.
Second, hospital systems must be prepared to protect healthcare workers who must be given priority for protective equipment and COVID-19 testing. Ventilators need to be available. Hospitals may not be the best place for all COVID-19 patients. In South Korea and in Italy, less ill patients are placed in hotels, dormitories, and newly constructed quarantine areas. Originally, this was done to limit the demand on acute hospital beds, but with experience it was found that these non-seriously ill patients actually do better than if they were in the hospital. Perhaps this is because they are less likely to be continually exposed to COVID-19. Third, we need to mobilize as a community to maintain food supply chain, transportation, security, and communications. We need to support and thank workers in these sectors.
There is a tendency to think the disaster scenarios are overblown. Psychologists call this natural human tendency “optimism bias.” This is not all bad, and, in fact, is a survival trait driving us to overcome adversity for a better future. Generals at war, doctors in emergencies, and great leaders in an economic depression project optimism but plan for the worst case and execute with the worst case in mind.
We will get over COVID-19 just as we get over hurricanes. It is estimated that this coming wave of infections will recede by the end of May (assuming we continue social distancing) and calm down by the middle of June. The key is to minimize the damage, maintain community cohesion, and emerge in the post-COVID period better and stronger.