It all began with China informing the world in Dec 2019 that a virus was spreading through their communities. The information seemed innocuous, with only a few deaths reported in the midst of the Chinese Lunar New Year festivities, its lethality hidden, partly by lack of knowledge about the virus, but also because of gross under-reporting of deaths.

But its ability to spread at an alarmingly rapid rate, as also its capacity to kill, have engulfed the whole world quickly. At the time of writing, COVID-19, as it has come to be called now, has infected more than half a million people in 201 countries across the globe and killed nearly 28,000.

And no one knows how far it will go yet!

COVID-19 is the latest from the family of viruses known as ‘coronaviridae’. This family is notorious for causing respiratory disease outbreaks, second only to the Influenza. The virus is simply a hull or a layer of fat around a protein/ genetic material.  By itself the virus is inert; it can only make more of itself by entering a living being. But it can also survive on various surfaces up to varying lengths of time.

The virus spreads mostly through tiny droplets in case someone sneezes or coughs close to you. It can also spread if you touch someone or something that is infected and then you touch your face, nose or eyes.  Once inside, the virus makes a beeline for your lungs, spleen or the intestines, where it can have the most dramatic effect.

The human lungs are lined with billions of epithelial cells; these are the border cells lining the lungs and mucosa.  Once the Coronavirus reaches these epithelial cells, it attaches itself to a specific receptor and releases the genetic material into the cell. The cell makes several new copes of the virus and then it simply self-destructs, releasing more and more of the virus, which then go on to attack other cells. The number of infected cells grow exponentially. After a few days, millions of body cells are infected and billions of viruses swarm the lungs.  The body’s immune system comes into action and immune cells pour into your lungs but the virus infects some of them too, causing confusion. Cells communicate through tiny information proteins called cytokines and nearly every important immune reaction is controlled by them.  Through them, the corona virus causes the immune cells to overreact and sends way more of them than required, wasting system resources and causing damage.

Two kinds of immune cells, the neutrophils and the T-cells respond. The neutrophils arrive in large numbers and start pumping enzymes which destroy the infected cells but also the healthy cells. The T-cells on the other hand order infected cells to commit suicide, but unfortunately due to the confusion, they order healthy cells to kill themselves too. The more immune cells that arrive, the more damage they do, killing the healthy lung tissue as well. This may get so bad that it causes permanent, irreversible, life-long damage.  In most cases, however, the immune system slowly regains control –  it kills the infected cells, intercepts the viruses and cleans up the affected areas. The recovery begins, and in most cases, the patient feels well after suffering mild symptoms.

But some cases become severe, even critical. With millions of epithelial cells dying, the lungs’ protective lining gets eroded, leaving the alveoli open to infection by bacteria. Patients quickly develop pneumonia and require ventilator support.  As the bacterial infection spreads, the immune system is overwhelmed and death will most likely occur.

The Coronavirus is much more dangerous than the ordinary flu, is definitely far mare contagious and spreads very rapidly too. There being no vaccine against the Coronavirus yet, social measures being the best protection at the moment. Things as simple as frequently washing your hands with soap and water to kill the virus are effective. Other measures such as social distancing, and the more extreme – early, complete lockdown to slow the pandemic, are vital.

There are also two outcomes for the corona pandemic …fast and slow. Which one will come about depends entirely on how we respond to it. The situation, as being faced by Italy, Spain and even the USA, is best avoided. Read The 21 Day Lockdown.

By the looks of it, the current Coronavirus pandemic appears to be a fast one, the kind that will record itself in the history books indelibly!

Herd Immunity

Herd immunity is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection

Quite opposite to slowing down the rate of spread through quarantine method, if the virus is allowed to spread, eventually so many people will have been infected and (if they survive) become immune that the outbreak will fizzle out on its own as the germ finds it harder and harder to find a vulnerable host. Therefore, when enough of the population is resistant to a virus, its spread stops naturally because not enough people are able to transmit it. Thus, the “herd” is immune, even though many individuals within it still are not.

Although it is ghastly to contemplate the prospect of billions being infected by the coronavirus, we have seen evidence for the emergence of herd immunity in other recent outbreaks. Many experts are modeling in their worst-case scenarios on unstoppable spread of the coronavirus. Simulations suggest that it could end up infecting about 60% of the world’s population, even within the year.

China, after initial bungling, ordered strict quarantine of affected areas, in order to stop the spread and regain control. Countries like South Korea, Singapore and Japan have opted for aggressive testing and identification of infected people. The patients are then isolated in an attempt to contain the disease.

Most countries in Europe, willingly or unknowingly, followed the herd immunity model initially and have thus witnessed a steep rise, only to attempt flattening the curve later. They are resorting to lockdowns, as the numbers are frightening and healthcare systems are unable to cope. The US appears to follow a mix of aggressive testing and herd effect.

India has chosen the quarantine method in deference to its own peculiarities and ground realities. Time will tell which approach works, if at all, there is some such thing. For the moment, the world is doing its best to cope with an enemy, unheard of in recent times.