Curbing the spread of COVID requires an understanding of evolution
Earlier this year, I wrote here about evolutionary processes that generate the ongoing parade of SARS-CoV-2 variants, the virus that causes COVID-19.
The newest sub variant of Omicron then was XBB.1.5, sometimes called the “Kraken” subvariant.
Because of mutations accumulated in that variant, it enters human cells more successfully than any previous variant. XBB.1.5 was “the most transmissible variant that has been detected yet” according to a World Health Organization (WHO) official.
It no longer holds that title. The same day I wrote that column, the WHO was announcing the appearance of XBB.1.16, “Arcturus”, the newest sub-variant in the omicron family.
Arcturus incorporates genetic material from two, earlier Omicron subvariants. It likely gained its new combination of genes when both of those earlier subvariants infected a person at the same time. As the victim’s hijacked cells churned out new viruses, some of those contained genes from both earlier strains.
The various mutations in the Omicron family continue to ‘tweak’ the spike protein of SARS-CoV-2. That outermost virus layer makes first contact with a host’s immune cells and other host cells suspectable to genetic hijacking by SARS-CoV-2.
As with other Omicron variants, this subvariant parade leads to increasingly transmissible and infectious versions.
Arcturus now occurs in 29 countries. It appears responsible for an ongoing surge of Covid infections in India. Less than a month ago, the active case load stood at 13,500. Five days ago, it was over 61,000.
While increasingly transmissible, Omicron subvariants don’t appear more lethal. It occurs in more than 20 states, including Ohio, but the U.S. hospitalization and death rate continues to decrease.
Natural selection and other forces of evolution give many people the sense that viruses like SARS-CoV-2 are “out to get us.” We tend to ascribe to them impossible tactical skills and evil intents. That’s not only wrong; it’s dangerous.
Health care providers often use an understandable, but technically incorrect shorthand when explaining symptoms of infectious diseases. For example, a recent article in Prevention magazine quoted an infectious disease physician explaining that Arcturus “likes to produce more high fever” than other Omicron variants.
No, it doesn’t.
Viruses don’t like anything. But natural selection can still favor traits found in Arcturus.
Effective public policy to control the spread and possible threat of SARS-CoV-2 variants requires a high-school level understanding of evolution.
We can’t change the mutation rate of SARS-CoV-2 or any other virus or organism. That depends on the genetic structure of the virus. In coronaviruses like SARS-CoV-2, that RNA-based genome is particularly prone to random mutations.
We can—and should—control the total number of new mutations and recombinations arising by reducing the global SARS-CoV-2 population. That requires widespread, international, and ongoing vaccination and other public health efforts.
Teaching such a biologically accurate, high-school understanding of evolution in the 2000s was a “controversial issue” deserving “both sides” treatment for some state Board of Education members.
Pending legislation in the Ohio legislature calls for teaching “both sides” of “controversial issues.” Neither evolution nor vaccination appear in the example list of the draft legislation. Then again, the legislation defines controversial issues as “politically controversial,” not scientifically controversial.
Just who’s controversies will require “both sides” treatment?
Steve Rissing is professor emeritus in the Department of Evolution, Ecology, and Organismal Biology at Ohio State University. steverissing@hotmail.com
This article originally appeared on The Columbus Dispatch: Rissing: COVID keeps mutating and we should work to understand it
