The advent and rapid prevalence of the Omicron strain demonstrates the potential of SARS-CoV-2 to evolve its ability to transmit and cause disease. What is particularly surprising, however, is that the origin of the Omicron strain does not appear to have originated from any of the dominant SARS-CoV-2 variants such as the Alpha, Beta, Gamma or Delta strains.
Similarly, however, the Delta did not arise from any of the branches of Alpha, Beta or Gamma. It therefore appears that despite intensive and unprecedented molecular surveillance of SARS-CoV-2 strains there is a significant gap in understanding the generative mechanism of variants of concern. The expectation would be to see the gradual collection of mutations in the prevailing strains until after a period of time a new troubling variant is created with different characteristics, something we have not noticed so far. So what is the way these “evolutionary leaps” are created?
The Professors of the Medical School of the National and Kapodistrian University of Athens (EKPA), Gkikas Magiorkinis and Thanos Dimopoulos (Rector of EKPA) report that there are various cases but some of them so far can not satisfactorily explain the phenomenon.
The first hypothesis is based on the so-called “hidden transmission”, ie branches of the virus that are transmitted in low numbers to the population but due to their low frequency do not happen to be sampled and have their genome “read”. However, this hypothesis seems to be the weakest as millions of genomes have been read to date and thousands of genomes are still read every day.
The second hypothesis of “chronic adaptation” is based on the observation that the virus in immunocompromised individuals can multiply over a long period of time. This results in a greater number of mutations than conventional infections as a result of its adaptation to the weak immune system of the immunosuppressed organism. Simply put, in people with weakened immune systems, the virus can persist for months and mutate to a large extent before being transmitted to other people. This case was first made about the Alpha strain when it was observed that it was in a long evolutionary branch as we observed in the case of Omicron.
The third “circular zoonotic” hypothesis is based on the observation that SARS-CoV-2 infects several animals such as felines, rodents and other mammals, and in the process of infection the virus acquires a series of adaptive mutations other than those normally developed in human infections. Also when the virus is transmitted between wild animals this results in no genomic sampling so the evolution of this branch in animals remains hidden. At some point, after several mutations have accumulated, the virus by chance reappears in the human population as a variant of concern.
In summary, it is extremely important to understand which of the above mechanisms create the variants of concern in order to enhance the epidemiological and molecular surveillance of the pandemic and to be able to predict in time the arrival of possible new pandemic waves. In any case, continuous genomic surveillance with publicly available molecular data is extremely important to solve the riddle of the origin of variants of concern such as Omicron.
Latest News
Athens Int’l Airport Wins Top Prize at Routes Europe Awards
The Routes business is focused entirely on aviation route development and the company's portfolio includes events, media and online businesses
IOBE: Income Gap Between Poor and Wealthy Greeks Widens
The findings in the analysis, entitled “Progressivity in Income Taxation in Greece, 2012-2021", paint a bleak picture for Greeks in the bottom half of the income bracket, warning that income inequality is growing
Study Finds 4 in 10 Greeks to Slash Easter Spending
This year, hit by persistent inflation, many Greeks will be dishing out less on food, drink and gifts for Orthodox Easter on May 5
ELSTAT: Overnight Stays in Greece Up in Feb.
The provisional monthly data revealed that arrivals at tourist accommodations amounted to 773,104 and overnight stays were 1,677,685
Electric Energy: Greece’s New Sustainable Export
Moreover, a surplus of generated electricity cannot be fully absorbed by domestic grids and this excess power finds eager buyers in the form of companies entering into Power Purchase Agreements (PPAs), willing to pay a premium for clean energy
IOBE Revises Greek GDP Growth Downward, to 2.1% For 2024
Annual inflation is expected to reach 3%, up from the previous forecast of 2.8%
Last Sections of 136km E65 Highway Inaugurated on Tues.
Athens to Karditsa drive time is expected to drop to two and a half hours (under normal conditions), and some three hours from Athens to Trikala
Reuters: Greece to Repay More Bailout Loans Ahead of Maturity in 2023
The country has relied solely on international markets for its borrowing needs since a third institutional bailout ended in 2018
Ag Min. Avgenakis: Greece-China Cooperation in Research, Education in Agri-Food Sector
Greek minister tours cutting-edge hydroponics and robotics facilities at the Chinese Academy of Agricultural Sciences in Beijing
Mini Holiday Season in Greece for Upcoming Orthodox Easter
Occupancy rates reach up to 90% domestically for accommodations open ahead of peak summer season