KATHMANDU: An overt COVID-19 epidemic may not be afoot in Nepal yet, but the confusion it has sowed is palpable. Confusion, fear and the ensuing paralysis are seldom constructive. But what really is the right way to respond in the face of a possible pandemic?

Should we recoil and hunker? Should we revel with abandon like spring breakers are doing in the beaches of Florida?

Lets look at this in two parts. First, how dangerous is the new Corona (SARS-CoV2) virus? Second, what should a rational person do about it?

At this point, the answer to the first question is painfully clear—really dangerous. Nothing-like-this-in-the-last-hundred-years dangerous. The last time the world saw a virus this dangerous was during the Spanish Flu pandemic of 1918 to 1920. That virus killed an estimated 50 million people, at a time when the world’s population was only 1.5 billion. In comparison, the First World War that ended in 1919 killed only about 20 million people.

It might be tempting to derive a false sense comfort out of the reported 1-3% case fatality rates for COVID-19. On its own, the case fatality rate does not offer much idea on how dangerous an epidemic can be. MERS has a case fatality rate of about 40%. But it is no where near as dangerous a public health problem as COVID-19 because the MERS virus does not spread as easily. SARS-CoV2, the virus that causes COVID-19 on the other hand, can spread like wildfire.

In order to make sense of fatality rates, it is important to understand the denominator in that math: the total number of people infected. If the SARS-CoV2 virus were to run amok it has the potential to infect up to 40-60% of the world’s population before it dies down (it won’t infect everybody for epidemic dynamics reasons). That’s about 3-5 billion infected people! At that point, even with a fatality rate of 1%, doing the math on the number of deaths feels like a grotesquely sadistic exercise.

That’s the worst case scenario, and may feel like a bit of an exaggeration. But is it? The Spanish Flu epidemic infected a third of the world’s population before it extinguished itself in 1920. COVID-19 and the Spanish Flu have similar epidemic dynamics.

How far epidemics spread depends on a viral property called the reproduction number—the number of secondary infections an index case is likely to cause when introduced in a susceptible population. The estimated reproduction number for SARS-CoV2 is between 2 and 3. Similar to what it was for the Spanish Flu. Seasonal Influenza on the other hand has a reproduction number just above 1 that goes down with rising temperature and humidity.

Epidemics like COVID-19 can be extinguished if we can push the effective reproduction number down to below 1. But there are no easy ways to do so. A vaccine could do so but we don’t have one for this virus, and none will be available for at least 18 months. Temperature won’t do it. Nor will turmeric for that matter.

And that brings us to the second question: what should our response be? Should we overreact and take excessive measures to protect ourselves? Or should we continue on with business as usual? The answer is much closer to the former than the latter.

Once an epidemic is underway, the only way to meaningfully reduce epidemic burden is to minimize individual contact. Our studies for Nepal show that we would have to societally reduce contact between people by about 50% to limit damage to the level wrought by the Seasonal Flu. Absent that, the damage done by an unmitigated epidemic will be orders of magnitude more.

Pandemic events like COVID-19 are what probability theorists call asymmetrically risky ruin events. The risk of an adverse outcome can be ruinous and dramatically eclipses the risk of the harm from an abundance-of-caution to prevent it. A rational person should do everything within their means to prevent an asymmetrically risky ruin event.

Being extremely cautious and surviving a pandemic certainly beats being six-feet under as a mere footnote in the cumulative death tables of history. Panic, fear and confusion won’t help, but this is also not a time to under-react and under-prepare. Or take chances.

Or as the Byrds sang:

A time to cast away stones

A time to gather stones together

This certainly is a time to come together as a society. And hunker down.

Pandey's book “Up Is The Curve—A Genealogy of Healthcare in the Developing World” is now available at Mandala Book Point.