Covid-19, the New Coronavirus, and Containment

posted in: Discovery, Musing | 0

A friend said that perhaps some governments are trying to claim high economic impact due to Covid-19 (the illness caused by the new coronavirus strain) while being seen as dealing with it effectively. That’s a one-shot strategy.

But it spreads so easily and its fatality rate is low enough, scientists are worrying that it could become endemic. SARS and MERS didn’t. They are no longer an issue. But if this strain of coronavirus becomes endemic, that will make it a problem every year, like influenza… and one-shot strategies will fail.

What are the implications for the world if it becomes an endemic virus?

It’s time to read up on viral evolution, because containment efforts will affect the way the virus evolves. Scientific American published a highly readable article about that many years ago. It is still pertinent. HIV and influenza are still relevant examples. Both mutate rapidly, but they are near opposite ends of the spectrum in terms of fatality rate and ease of spread.

HIV in particular startled scientists as prevention campaigns took hold. In places where it could spread easily, such as Africa, it became more lethal. In places where ‘safer sex’ made it harder for HIV to hop to new hosts, it became less lethal. In the absence of effective treatments, it still caused a uniformly fatal disease. But where its spread was hindered, it didn’t make people as sick as fast.

HIV evolved so that where it could not infect people as easily, it kept its hosts less sick for longer so it had more time to find new hosts. We regard viruses as simply being chunks of genetic material with no capacity to think, so to most scientists this came as a surprise. Evolutionary pressures can have an effect that looks a lot like conscious planning.

Right now the new coronavirus can infect people very easily and it kills a higher proportion of patients than most strains of influenza. If it continues to have such an easy time spreading, it can afford to kill a higher proportion of its hosts than it does now. In other words, it can afford to evolve to be more deadly.

Containment measures such as quarantine or wearing N95 or FFP2 face masks make it harder for the virus to spread. In the short term, that simply reduces the number of people who get sick with it in this epidemic or pandemic.

The long term effect may be more important. If the virus has difficulty finding new hosts, that creates evolutionary pressure for it to make people less sick… and then it would be less of a problem if it becomes endemic.

DISCLOSURE: I am not a medical professional. However, I am a professional problem solver who has always loved science. All I have done here is connect the dots from publicly available scientific articles. An epidemiologist may be able to poke holes in what I have said here, or refine it.

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