Beating the virus: Why social distancing is imperative at this juncture in time

By Dr. Sumedha S. Amarasekara

I have borrowed the first part of my title from the editorial of The Island, 9.08.2021. This is indeed a timely editorial that highlights the importance of what we need to do while providing a social criticism of our failure to do the right thing. I intend to provide a biology-based justification for the second part of my title.

In order to understand why social distancing, washing hands. etc., is so important one needs to have a basic understanding about viruses. ‘A virus exists for the sole purpose of making more viruses’- Richard Dawkins (The greatest show on earth, Arms races and ‘evolutionary theodicy’, page 391)

Viruses are genetic materials (DNA or RNA) covered in a special coating of protein called a capsid. Once a virus enters a body/cell, it hijacks the protein making machinery in the cell to churn out more viruses; instead of making whatever products/molecules these cells were supposed to be making. This process results in us getting ‘sick’. The ultimate outcome following viral infection is ‘death’ of the virus. This happens in two ways; either the host’s immune system overcomes the virus and gets rid of it/kills it. Or else the virus overcomes the host, causing it to die. At which point the virus, no longer having a host, dies as well. While this is happening, the virus will (try to) spread to another host.

The capsid of the virus begins to degrade once it is outside the human body. Once these capsids degrade to a certain extent the virus cannot ‘survive’. Therefore, a virus needs a host in order to survive. From the perspective of the virus, once it leaves a host, it is imperative that it finds another host before its capsid loses its integrity.

This is why all the decontaminating processes, washing hands etc., and social distancing is so important in the prevention of spread of the Covid-19. As to why it is imperative at this juncture in time, needs a little more explanation with regard to the theory of evolution and as to how vaccines work.

 “The Origin of Species by means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life” is the title of the revolutionary publication of Charles Darwin in the year 1859 that changed our view of life on earth. Charles Darwin showed that this earth we live in, is not some paradise, but a constant battlefield where all living organisms are constantly battling each other for existence. Be it a tree growing taller to get more sunlight or an antelope running faster to get away from the cheetah. The importance is that this theory not only applies across species but also within the species as well. Every member of a species is in a struggle for ‘survival of the fittest’.

As mentioned earlier, the virus hijacks our cellular process to make its progeny. In this replication process ‘mistakes’ happen. The scientific name for these mistakes is mutations. Scientists have pointed out that, viruses keep mutating all the time. These mutations result in the resultant viruses being different from its predecessors. The degree of difference depends on the particular type of mutation. Following a mutation, a different virus is released in the host. This virus will now in turn infect the host and try to spread from this host to another. If a considerable change takes place to make it significantly different from its original counterpart it will be legitimately recognised by scientists as a variant. This is the explanation for the different variants we see with regard to the Covd-19; Alpha, Beta, Delta variants and so on.

These different virus mutations /variants need to compete among each other to gain access to a host-us humans in this case. Whatever particular mutation is most successful at this, becomes the dominant mutation/variant at that time and is responsible for the spread of the virus. As time passes the hosts begin to develop an immunity to a particular mutation that predominates, as this happens another mutation takes over. This is what we have being witnessing with the Covid-19 as well. Currently in Sri Lanka and the world it is the Delta variant that is spreading.

Ignoring the specific scientific process behind vaccination, vaccination can be described as a process by which our immune system is given the ability to unleash a lethal force on the relevant organism before it even knows what is happening. After a successful vaccination process the host is rendered immune to that particular agent. For example, Polio vaccination has more or less helped get rid of Polio from the world. If you are vaccinated and you have developed an immunity to the Polio virus, you cannot get it. The virus is stopped dead by our immune system. The virus cannot manifest as the disease Polio, the virus cannot spread to another person.

Whatever Polio viruses that enter our body are killed.

Unfortunately, the Covid-19 vaccine, regardless of a particular brand, does not make one immune to Coivd-19. Despite being vaccinated, one can get Coivd-19, manifest the disease and even transmit it to another person. What the scientific evidence indicates is that, vaccination leads to a decrease in the morbidity (severity) and mortality of the disease. In this way, the current Covid-19 vaccine is similar to the seasonal flu vaccine.

In the absence of vaccination, all of the different mutations of Covid-19 are more or less on an equal footing to gain access to a host. However, in the presence of a vaccine that gives only partial protection, the dynamics for this challenge change dramatically. Now, those variants that have some innate resistance to the vaccine are at a huge advantage in comparison to their fellow variants that are susceptible to the vaccine. Therefore, these mutations/variants tend to start spreading overtaking the other variants. And as one can see. as explained by the theory of evolution each ‘successful’ mutation will be better at overcoming the vaccine than its predecessor.

Those among us who have got the first dose of the vaccine and have developed some immunity-but not the complete immunity-will be playing a key role as catalysts in this process of evolution of the virus! As can be seen from this process of evolutionary logic, (in the absence of a definitive vaccine) ironically those who have been vaccinated, especially those who have just received the first dose – are more relevant than their counterparts that have not been vaccinated in the evolutionary selection and spread of the virus.

Therefore, in the face of an accelerated vaccination programme, it cannot be overstressed that we must follow the rules of social distancing, hand washing, etc., The only way to combat this virus is to make sure that we isolate ourselves as much as possible, thereby blocking the transmission of this virus. ‘The virus can be beaten decisively if we get our act together’ as mentioned in the concluding sentence of the editorial.

It is important to understand that ‘What does not kill you, only makes you stronger’ applies not only to us but to the virus as well.