Corona Daily 056: How will the Covid Pandemic End? When?

Predicting the future is dangerous business. We live in a misinformation age, where accurately knowing the past is challenging. The pandemic end-date is something everyone is desperate to know about, and few would dare to foretell. India’s PM Modi declared victory in January, and was proved wrong. UK’s PM Johnson had announced 21 June as UK’s Freedom Day (from the virus), now the threat of the Delta variant has postponed British freedom by four weeks.

Over today and tomorrow, I will risk foretelling the end date of the pandemic. I will use logic, available research, analysis of history, opinions of various epidemiologists, and statistics. Of course, the prediction can go wrong. But then, unless you have a railway timetable, how will you know how late the train is?

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In my research, I came across two interesting concepts. One is a concept in biology called “self-limiting”. It particularly relates to parasites. A parasite can enter your tummy; start multiplying in millions, billions to cause serious gastrointestinal diseases. Nature is a master designer. Parasites, like viruses, have no brains and certainly no souls. By occupying the host’s guts, the parasite colony will harass the host, make his life miserable. However, it will not grow beyond a certain number, for fear of killing the host. If the patient dies, the parasites’ life would end as well.

To give an analogy: Imagine a corporate husband working hard, earning a decent package. His non-working wife is fond of spending. There is an ongoing race between his earnings and her spending. The innate wisdom of the wife makes sure she will not spend so much as to cause divorce, lose the husband, and her credit cards. (Sorry for the sexist analogy, but it is a historical stereotype that is easier to relate to).  

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In medical science, this beautiful concept of Nature results in Self-Limited diseases that resolve spontaneously. We are familiar with mild ones like the common cold, flu, conjunctivitis, or simply headache or back pain. They can all be self-limiting in that they will go away on their own, without any treatment. There is a long list of diseases that neither I nor my spell check recognize: Epiploic appendagitis, mesenteric adenitis, pericardial fat necrosis, omental infarct and so on. Maybe we don’t hear about them because they are self-limiting.

My key take-away from the concept is that lots of things in nature are self limiting, so are pandemics. Every single major pandemic in history came to an end, so will the current pandemic.

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Error Catastrophe is an expression I had never heard before the pandemic.

By now we all know viruses mutate. Earlier I had mentioned that the covid virus uses our living body as a photocopier, and keeps making copies of itself. This replication process is not perfect, the virus keeps on making mistakes, its copies differ or in other words mutate. We know that the mutations (now a lesson in re-learning the Greek alphabet) help the virus escape recognition by the immune system. A certain mutation can be more transmissible, faster spreading, or deadlier. Some mutations can even escape or reduce vaccine effectiveness. This has given us great cause for concern. What if the number of mutations keeps growing and goes beyond the Greek and all other alphabets?

Well, it is unlikely. The principle of Error Catastrophe explains why. If the virus makes too many mutations, it usually loses some of its biological features which have evolved to its advantage, including the ability to reproduce at all.

The Darwinian principle of ‘survival of the fittest’ applies to the virus as well. In the first few mutations, the virus is fit. After reaching a certain number, it loses its potency. Mathematicians are always working with hideous-looking formulas to arrive at that number.

In fact, some scientists are trying to use this concept to create a new antiviral medicine. Any replication system has a maximum error rate beyond which the original genetic information is gone. The antiviral medicine tries to use this rate to disrupt the virus’s replication ability.  

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(Continued tomorrow)

Ravi