Actually, it's only the second anniversary of the pandemic, but with a nod to Paul Simon, it appears the causative virus is still going crazy after all these years.
After two years of Covid 19, more than 50 million Americans have been infected with the virus and more than 800,000 of us have died. And that is just confirmed infections and confirmed deaths. As evidenced from the national data on excess mortality, the real number of Covid cases and deaths is almost certainly higher.
The number of cases is surging again—the time the northeast and upper midwest are being hit the hardest. Experts predict that cases, hospitalizations, and deaths will continue to climb into 2022, and the winter surge will spread to other parts of the country before it abates.
Covid cases over time. We are seeing the beginning of another winter surge. Taken from the New York Times website.
Evolution of Covid—a numbers game
Alas, the longer the virus is with us, the more likely a variant of concern is likely to occur (evolve). Each infected human carries 1-100 billion viral particles (virions) at peak infection. In other words, the virus has had to make copies of itself (replicate) more than a billion times from its one DNA blueprint in each infected person. With over 50 million people infected, the number of virions produced surely exceeds a quadrillion—and that's just in the US. .
Like anyone or any thing copying something a quadrillion or quintillion times, mistakes are made. Mistakes in copying viral DNA usually lead to the manufacture of a faulty protein. Since the virus needs a relatively small number of specific proteins to build a copy of its tiny self, a defect in any protein may make it impossible to make a functional virus. That virus would die out and the mistake is not perpetuated.
Variants—trend towards more infectivity and less virulence
Sometimes, the copying mistake leads to a protein that Is not only functional, it actually confers a survival advantage on the virus. If the abnormal protein can make the new variant of the virus more infectious (for instance, easier to transmit or more efficient in infecting a human) it may out-compete the previous version of the virus and come to dominate a population. That's been the case with the alpha, beta, and delta variants to date,
The general trends in the evolution of respiratory viruses is towards more infectivity and less virulence. After all, if a virus doesn't kill the person it infects, more copies of itself will be made and sheer numbers will ensure its spread in the population. Moreover, more people will get re-infected and start the process all over again.
The evidence is scant as yet, but it does look as if the Omicron variant may be following that strategy.
Covid cases per 100,000 in the week ending December 10, 2021. Graph and date taken from the New York Times website.
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