By JAMIE MAGRILL & ALEXANDRA MARKUS HUTZ
In the three weeks since I wrote Coping with COVID-19, part 1: Country and society, the world has progressed to an eye-popping 1.7 million confirmed COVID-19 cases, more than 100,000 deaths and over 10,000 cases in Israel itself. Economies have begun to groan under the strain of massive unemployment, issuing billion or trillion-dollar bailout packages, while overtaxed healthcare systems crack under the weight of new cases in places like New York, Spain, and England. It’s not all bad news however; in China, workers are beginning to return to their factories, South Korea has shown massive improvement without employing draconian lockdowns, and in Israel the number of new cases has just started to plateau amid an increasingly strict lockdown during the Passover holiday.
In my last article we explored some common misconceptions about the novel coronavirus and its epidemiological, societal and economic impacts, as well as tips for staying healthy and uninfected during the pandemic. In this piece, we will discuss some of the more precise personal concerns about COVID-19, address new myths about the pandemic, and discuss how viruses operate, thrive and move through populations. It’s important to note that as writers, we have no specific training in public health or epidemiology – both authors are scientists (one biologist and one epidemiologist), so our perspectives are based on the same news articles and books everyone else has access to, just with a bit of scientific skepticism added to the mix.
Why is the coronavirus so deadly for some folks and not others? Right now, we know that COVID-19 is significantly more deadly for the elderly, those with compromised immune systems or preexisting conditions. Scientists and doctors are unsure why exactly; that will take comprehensive reviews of patients and virus behaviour, which takes time. We do know that in many severe cases COVID-19 triggers a cytokine storm, causing the immune system to attack the lungs and preventing the patient from breathing properly. This can prove fatal if the patient is not put on an artificial ventilator, which is why governments and healthcare systems are so concerned about global availability of ventilators.
How do cytokine storms work? Our immune systems are constantly walking a fine line between under and over-activity; too little response and a foreign pathogen can wreak havoc, as with the immune-compromised, while too strong of a response can cause immune cells to attack the body’s own tissues like in anaphylactic shock or auto-immune conditions. Sometimes, when the immune system becomes overwhelmed, especially with a brand new pathogen like the coronavirus that our bodies have never experienced, it begins to go into overdrive. When this happens, the negative feedback loops that are meant to keep our immune system in check can fail as a massive amount of cytokines (a type of inflammatory signalling molecule) are produced. Cytokines attract immune cells which begin to attack the pathogen, and as the immune cells produce more inflammatory signals, this can eventually cause too much inflammation for the body’s tissues to handle. This process can be life-threatening due to systemic hyper-inflammation, hypotensive shock, and multi-organ failure.
How did we get from 70,000 cases in Wuhan in February to 1.7 million cases worldwide today? Recently during an interview Dr. Anthony Fauci, head of the USA’s COVID-19 response team, admitted that a respiratory-borne virus with a long incubation time and a relatively high death rate was the perfect storm of conditions for a deadly, worldwide pandemic. The novel coronavirus fits all of these conditions perfectly, and is particularly dangerous for specific segments of society (the elderly, the immune-compromised, and those with preexisting conditions), placing additional strain on our healthcare systems as they are forced to deal with unprecedented waves of difficult-to-manage patients with complicated underlying health conditions.
The coronavirus spreads so quickly because of its long incubation period (1-14 days) with an average of 5 days before symptoms present themselves. Once symptoms are present they generally resolve over several weeks and the person self-isolates, reducing transmission. However, in a minority of cases patients decline rapidly and require intensive care and even artificial ventilation (Prime Minister Boris Johnson, who required admission to intensive care after more than a week of mild symptoms, is a good example of this phenomenon). However, between 50-85% of all coronavirus patients may be asymptomatic, drastically increasing the potential of the virus to spread insidiously through communities before being noticed.
To put into perspective why we need social distancing and self-quarantines to reduce the spread of COVID-19, suppose one person with COVID-19 is asymptomatic for 5 days (exactly the average time before symptoms present). During those five days, this person travels to and from work by bus (four people nearby on each bus ride), interacts with three colleagues per day at work, and goes shopping once (four people nearby in the checkout line). As a ballpark estimate, this person probably interacted with fifty people over five days. Conservatively, even if this person only infect 5% of the people they interact with, that equals 2.5 new infections. These people then go out into the community, asymptomatic, and over 5 days infect another 2.5 people each, bringing the total to 8.5 people infected after 10 days. With a doubling time of around 3-5 days, after just 30 days, there are around 1000 people infected; after 60 days, around 1 million people infected. This exponential curve is exactly what we are seeing with COVID-19, which has an R0 (estimate of the average number of people who catch the virus from a single infected person) of 2-3.
Now let’s replay this scenario, but with social distancing and quarantines for exposed individuals. The asymptomatic person takes the bus just once in five days, as they are working from home (two people nearby on the reduced public transit service), goes shopping once (two people nearby in the checkout line) and goes out walking once per day (one person nearby per walk). In total, the infected person may have interacted with ten people in five days. Even if they manage to infect just one new person, after five days they present with symptoms, arrive at the emergency department, test positive and through contact tracing all the exposed people are put into self-quarantine, cutting off the transmission chain before it spreads. This difference, which changes the R0 from 2 to 1, is the most powerful tool we have right now to fight the virus, but it relies on everyone cooperating until the outbreak is brought under control.
Since the curve seems to be flattening in many hard-hit places, can we stop self-isolating now? Unfortunately, no. Even though the numbers of new cases are decreasing, they are still in the hundreds or thousands and need to decline further before we can relax social distancing policies, or we will just repeat the outbreak cycle again. Every day we continue to social distance and self-isolate, we give our scientists and healthcare workers time to build the testing and tracking infrastructure needed to prevent new outbreaks in the future.
Yes, social isolation is challenging and mentally taxing, but through it, each of us has the power to make an impact for the public good, and the potential to save lives. We all have a moral duty to help curb the spread of COVID-19.
This article was written as a collaboration between Alexandra Markus Hutz, an adjunct professor of biomedical sciences at Shelem College, and Jamie Magrill, a Masters of Science student at the Hebrew University of Jerusalem.