Nikhil Prasad Fact checked by:Thailand Medical News Team May 17, 2025 1 day, 4 hours, 5 minutes ago
Medical News: Omicron May Represent a Major Turning Point in the Evolution of the COVID Virus
A new scientific review by Dr. Anju Kaushal from the New Zealand Organization for Quality in Palmerston North is raising alarms in the medical and scientific community. The study suggests that the emergence of the Omicron variant of SARS-CoV-2 may not be just another mutation, but a possible example of what is known as an “antigenic shift”—a major change in the virus’s structure that allows it to escape immune detection and potentially behave more like a different virus altogether.
Omicron Variant Could Signal Dangerous Shift in COVID-19 Virus Behavior
The possibility of such a shift is deeply concerning because it means that existing immunity—whether from prior infections or vaccinations—could be significantly less effective. This
Medical News report explores the significance of these findings and what they mean for the future of COVID-19.
What Makes Omicron So Different
Since the beginning of the pandemic, several variants of SARS-CoV-2 have appeared, including Alpha, Beta, Gamma, and Delta. These were all considered “variants of concern” due to their increased infectivity or ability to evade immune protection. But Omicron—first identified in South Africa in late 2021—stood out immediately. Unlike previous variants, Omicron carries more than 50 mutations, many of which are on the spike protein, the part of the virus that helps it enter human cells.
Some subvariants of Omicron, like BA.2 and BA.5, became dominant in various regions due to their higher transmissibility. BA.2, in particular, had nine new spike mutations compared to its predecessor, BA.1, making it more contagious. Researchers also identified mutations in important viral regions like ORF1ab, ORF7a, and ORF10, many of which contributed to immune escape and decreased vaccine effectiveness.
The virus continued evolving, giving rise to highly mutated and evasive subvariants like XBB, XBB.1.5 (nicknamed Kraken), and XBB.1.6 (Arcturus), which have shown a similar or even higher binding affinity to the ACE2 receptor—critical for viral entry into human cells. These variants also appear to resist neutralization by existing antibodies, even those developed after booster vaccinations.
Omicron and Immune Escape
One of the most alarming aspects of Omicron is its ability to dodge immune responses. Mutations such as D614G, E484A, N501Y, and K417N help the virus evade antibodies produced either by vaccines or prior infections. Additionally, newer mutations like R346T, K444T, F486S, and N460K in subvariants like BQ.1 and BQ.1.1 make it even harder for the immune system to recognize the virus.
These subvariants have shown reduced effectiveness against many monoclonal antibody treatments and vaccine-induced antibodies. For example, sera from individuals who had received three or even four vaccine doses struggled to neutralize newer variants like BQ.1 and XBB.1.5.<
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Breakthrough Infections and Hybrid Immunity
Although the Omicron variant is better at evading immune defenses, it often leads to milder disease, especially in vaccinated individuals. Breakthrough infections—where vaccinated individuals get infected—have become common. While concerning, these infections can sometimes provide a form of “hybrid immunity,” a combination of vaccine-induced and infection-induced protection that may help shield against newer subvariants.
However, the protection appears to be short-lived. Many studies now indicate that a third or even fourth vaccine dose (often with a bivalent formulation targeting Omicron) is necessary within a few months to restore sufficient antibody levels.
The Role of T Cells and Antigenic Mapping
While most studies focus on antibodies, T cells—another critical part of the immune system—also play a role in fighting infections. Unfortunately, the Omicron variant seems to affect how T cells recognize the virus. Mutations in specific regions may disrupt the activation of CD8+ T cells, which are essential for destroying infected cells. In elderly or immunocompromised individuals, this can lead to more prolonged infections, giving the virus more time to mutate.
To better understand how the virus is changing, scientists are using a method called antigenic cartography. This technique maps how different variants are recognized by the immune system. Recent studies using animal models, such as Syrian hamsters and non-human primates, have shown that Omicron variants like BA.5 and XBB.1.5 are far removed from earlier strains like Alpha or Delta. This supports the idea that Omicron could represent a true antigenic shift.
New Tools and Future Vaccines
Because Omicron continues to evolve rapidly, researchers are exploring new ways to fight it. One promising area is nanobody therapy. Nanobodies are tiny antibody fragments that can be administered via inhalers to directly target the lungs, where the virus tends to concentrate. Some experimental nanobodies have shown the ability to bind tightly to the spike protein and block infection.
Next-generation vaccines are also being developed. These include intranasal vaccines, which may generate strong mucosal immunity in the nose and throat—areas where the virus typically enters. These vaccines may be more effective at preventing transmission and could serve as important tools in future outbreaks.
Another approach involves designing vaccines based on nanoparticles that present stable versions of the virus’s receptor binding domain (RBD). Early results show that these vaccines can produce a strong immune response even after a single dose.
Why This Matters Now
The study makes it clear that Omicron is not just another variant—it may be the beginning of a new phase in the virus’s evolution. The mutations seen in Omicron and its subvariants give it a clear advantage in spreading through the population, even among vaccinated people. While the disease it causes may be milder, especially in healthy individuals, the constant mutation means that we can never be sure when a more dangerous version might emerge again.
The evidence also supports the idea that Omicron may have originated in immunocompromised individuals or even jumped from animals back to humans in a process called reverse zoonosis. This raises the need for stronger surveillance—not only in human populations but also in animals that may act as viral reservoirs.
The study findings were published in the peer reviewed journal: COVID.
https://www.mdpi.com/2673-8112/5/5/73
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Read Also:
https://www.thailandmedical.news/news/austrian-study-finds-that-sars-cov-2-omicron-strains-exhibits-greater-cardiotropism-than-previous-variants
https://www.thailandmedical.news/news/study-reveals-neurological-dangers-of-mild-omicron-subvariants
https://www.thailandmedical.news/news/new-alarming-case-shows-omicron-and-newer-sars-cov-2-strains-can-still-damage-placenta-in-pregnant-women
https://www.thailandmedical.news/articles/coronavirus
https://www.thailandmedical.news/pages/thailand_doctors_listings
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