Many are wondering when the SARS-CoV-2 epidemic will end if the strategy of “not resisting the virus” is continued? Perhaps the answer to this is in a new discovery by scientists who discovered that an epidemic of a new coronavirus began in Southeast Asia 25 thousand years ago. It is not known whether this epidemic continued constantly or returned after several years, but the coronavirus has exerted serious selective pressure on humans. It is also unknown whether he exerted pressure by the fact that he was highly virulent and fatal in himself, or perhaps by simply crippling people with his “postcoid” and other serious consequences for their health and reproduction. However, man tried to adapt to it genetically. And only after 20 thousand years, 5 thousand years ago, it succeeded: the coronavirus ceased to be scary. Since a person resistant to it was “brought out”.
Recall that in recent years, coronaviruses have become the culprits of two major outbreaks and one pandemic, which continues to this day. The first alarm bell rang in China in 2002, when SARS-CoV infected more than 8,000 and killed more than 800 people. Four years later, MERS-CoV (Middle East Respiratory Syndrome Coronavirus) emerged, affecting over 2,400 and killing over 850 people. And finally, at the end of 2019, SARS-CoV-2 appeared in China, provoking the ongoing COVID-19 pandemic. And today we are dealing with numerous strains of it.
… But in reality, we have been battling coronaviruses for millennia. A new study, published in the scientific journal Current Biology, showed that an ancient coronavirus epidemic broke out in East Asia about 25 thousand years ago, and humanity could not recover from it for several millennia. Evidence for this can be found in the genomes of modern humans from this region. This conclusion was reached by a group of scientists from Australia and the United States based on the study of the genomes of peoples living in East Asia.
The culprit for the ancient outbreak, according to their version, was a virus that interacts with human cells and tissues in a similar way to the virus that caused COVID-19. According to a biologist from the Queensland University of Technology, one of the authors of the study, Kirill Alexandrov, that epidemic wreaked havoc on the population and left significant genetic scars, which is now recorded in the genes of the descendants of people who survived it: like the rings of a tree, our genetic code can tell about the events of our ancient of the past.
Random mutations in our genes mean that some people are naturally more susceptible to contracting viruses or developing serious symptoms of disease. For example, studies have been conducted around the world showing that people carrying a cluster of genes inherited from Neanderthals about 50 thousand years ago have a higher risk of developing severe symptoms of COVID-19. The good news is that other mutations have the opposite effect, and may give us a survival advantage in disease outbreaks. Evolutionarily, people who have inherited such variants of genes are more likely to survive and reproduce, however, over several generations it happens that the frequency of favorable variants of genes increases.
A group of international scientists used the human genome database to figure out how the ancient coronavirus epidemic shaped our genes. They calculated that it takes at least 500-1000 years for the signal of surviving “adaptive markers” to appear in the genome of a population. So humans could have ancient encounters with coronaviruses that could show up in our genome.
The study examined the genomes of thousands of people from all over the world, stored in the database of the 1000 Genomes project. And only Asians were found to have genes that helped them survive the ancient coronavirus outbreak. Adaptation genes were found only in the inhabitants of Vietnam, China and Japan, however, alas, they were not found in the inhabitants of other parts of the planet.
The next stage of the work was to calculate how long ago this adaptation could have occurred. It turned out that it began about 25 thousand years ago. At the same time, evolutionary pressure on genomes is supposed to have stopped only 5 thousand years ago. That is, it took the Asians about 20 thousand years to adapt to the “crown”!
Scientists cannot say for sure whether the ancient pandemic was outbreaks, for example, seasonal, like the flu, or was constantly present. It cannot even be ruled out that the ancient coronavirus was periodically transmitted to people through animals. However, the mechanism of cell penetration in the archeo-corona was similar to that of modern SARS-CoV-2.
By the way, there are other studies in the world confirming that the family of viruses, to which SARS-CoV-2 belongs, arose about 23-25 thousand years ago. But in any case, it is clear from the study that humans have been exposed to coronaviruses for about 20,000 years.
“There have already been works that suggested that the relatively low mortality rate from covid among Asian peoples is just a consequence of similar epidemics many centuries ago, thanks to which stronger immunity was formed than among Europeans,” says molecular biologist Tatyana Perfilieva. – It follows from the work that human adaptation to those coronaviruses took so long precisely because of their low virulence. But it cannot be ruled out that it was a series of micro-epidemics. The tribe was catching a flock of bats (pangolins, camels, etc.) infected with some kind of coronavirus. Half of the tribe, which did not have the right genes, died out, the other half, who had the right genes, remained alive. And so it was repeated thousands and thousands of times. In any case, some people have acquired a genetically determined protection against coronaviruses, which has been acquired for 20 thousand years, but how exactly this happened, they do not know. “
Why is this research important? Scientists note that unraveling the evolutionary history of past coronavirus outbreaks could provide clues on how to respond to future pandemics. This information says a lot about how viruses spread and how long they have been around. And tracking genetic adaptation can help researchers pinpoint which genes are key players in our body’s response to infections. Which, among other things, can help in the development of drugs and vaccines. Professor Aleksandrov says that with such information before the COVID-19 pandemic began, we could take several steps forward in our response. This would help to quickly find effective drugs and, possibly, accelerate the development of vaccines.
Some experts warn that in today’s world, factors such as access to health care and good hygiene are more important than genes in determining whether or not you get sick.
And while the idea of being exposed to coronaviruses for 20,000 years sounds daunting, there are some comforting moments. Still, 5 thousand years ago, mankind had neither medicines, nor vaccines, nor a water supply system with sewerage, nor modern achievements of medicine. In addition, even with the Spanish woman at the beginning of the last century, they managed to cope. This means there is a chance that the coronavirus will be brought under control much earlier.
As Konstantin Severinov, Doctor of Biological Sciences, Skoltech Professor, told MK, we can safely say that there is a certain natural resistance to the new coronavirus right now: “After all, a lethality rate of 1% and a large number of asymptomatic infections means resistance of many people. On the other hand, the fact that the virus most severely infects older people in the post-reproductive age means that its impact on future generations will not be large. In any case, human conditions have changed dramatically. In addition, the rate of spread of ancient epidemics is not comparable to the current one, when more people live on Earth and there are much more contacts between them. In general, we will not have to wait 20 thousand years for the end of the pandemic, hoping for a change in the genetics of the human population. Most likely, it will fade away within a few years, after everyone is ill or vaccinated. Both the vaccinated and those who have recovered will become infected, but they will get sick easily. Children will be born who will easily carry the infection in childhood and continue to follow through life with a certain level of acquired immunity. That is, the virus will stay with us, but it will pose much less danger to us. The case of infection will no longer be the reason for PCR tests, quarantines and self-isolation. Today, alas, most of the population has not yet been ill, and if the pandemic developed naturally, it would take many years for everyone to get sick. On the other hand, in less than a year, 6 billion vaccine doses have already been used: this means that at least 3 billion people received at least one dose, which is almost half of the world’s population. So vaccination is a faster, and certainly less painful, way to acquire immunity. “
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