Happy Anniversary Covid-19

"Do lockdowns cause more virulent and lethal strains of Covid-19 to emerge?"

A couple of weeks back, we reached the anniversary of Covid-19. While we remember the victims, let's celebrate. Over the past 12 months, we've learnt a great deal with the advances made on vaccines, nothing short of remarkable. These innovations place us in a strong position when the next pandemic arrives. But there is much we have yet to understand.

For example, do lockdowns cause more virulent and lethal strains of Covid-19 to emerge? While this may appear an odd question, understanding how evolution works means further examination is needed. Undoubtedly lockdowns curb the spread of all variants you assert. That's not the case. It helps to consider human behaviour as a factor. Dr Paul Ewald, an evolutionary biologist from Massachusetts, believes the lethal strains enjoy a boon due to our actions. Let me try to explain. 

We know that the RNA in a virus undergoes constant random mutations. There is no plan at work here, only haphazard processes. What is essential to note is that specific mutations gain an advantage because the environment favours their spread. After all, the virus seeks to do one thing, move from host to host. 

Thus, virulent strains that kill the host quick are unlikely to move into the broader population because the transmission chain is cut. To illustrate the point, Ebola doesn't enjoy much contagion because it rapidly turns the victim's insides to a mush. The game is up before the virus can reach lots of people.

During the 1918 flu outbreak, the initial virus was relatively weak and mild in symptoms. Thus soldiers who caught the flu remained on post in the trenches. This gentle form spread without any significant impact. 

Then came a second wave with a mutated virus that proved more severe in symptoms and was lethal for many. In particular, this strain hit people of fighting age hard. In response, the military removed the infected from the front-line through clearing stations and into hospitals at the rear. This process gave the virulent strain an advantage that allowed it to move into a much larger population. 
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As the more virulent strain kept people immobile, unable to care for themselves, others attended them. Stretcher-bearers, orderlies, nurses and doctors all came into contact with the carriers. We thereby provided a route for transmission. 

With Covid-19, we've seen some correlation between places that implemented strict lockdowns and the emergence of potent variants. For instance, the United Kingdom. Whereas places like India and Hong Kong have had no virulent strains appear.  Only the milder forms of Covid-19 dominated, even though both India and Hong Kong are crowded.

The hypothesis is that by locking down a population, you keep people static in one place, and thus the mild variants cannot move around. In that sense, you achieve your aim. But, when a new, more potent strain emerges, you transport the sick to a hospital and into care. That movement provides the opportunity for the virulent strain to pass into the wider community. Our response gives the nasty mutation an advantage.

It's important to stress that this is a theory. We need a study, using statistical models allied to the tracing of individual strains to verify the idea. Also, it is not that we dismiss the merits of lockdowns. Please don't lose sight of how we are dealing with a complex dynamic system of virus transmission. Lockdowns will keep a role, even if the theory proves correct. Still, we may adjust these to minimise the leg-up we give virulent strains and reduce community-wide deaths. 

The obvious conclusion is that there is much to learn and celebrate.