EG.5 (Eris): The Latest Variant of Interest in the COVID-19 Saga
Insights, Impact, and Key Considerations
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In this edition, we will take a closer look into latest COVID-19 variant of interest, a descendant of Omicron called EG.5 or colloquially referred to as Eris (nicknamed after the Greek goddess of strife and discord). EG.5 is making headlines since summer and for valid reasons. This particular subvariant of COVID-19, EG.5, is spreading rapidly on a global scale, resulting in a notable surge in both cases and hospitalizations.
The World Health Organization's Initial Risk Assessment Report highlights EG.5's prominence, accounting for a significant 49.1% of reported cases during the period spanning from June 19 to July 23, 2023. The report described EG.5 “has shown increased prevalence, growth advantage, and immune escape properties,” but “there have been no reported changes in disease severity to date.”
Naturally, questions arise. Should we be alarmed? What symptoms are associated with EG.5? Can boosters provide a solution? Is there a dedicated booster designed to address this new variant?
The process of monitoring and understanding the behaviour of each COVID-19 variant is a demanding task. I’ll admit, following Omicron variant, I intentionally avoided updates, research articles, and any details about emerging COVID-19 variants—up until now. Interestingly, this new variant has piqued my curiosity. This article is dedicated to tackling the concerns arising from the rapid spread of EG.5, the most recent offspring of the Omicron lineage.
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Why EG.5 Earned its Place on WHO’s “Variant Of Interest” List?
EG.5 - The Basics
EG.5 is like a remix of its cousin, the XBB.1.9.2 subvariant. But, it's got a trick up its sleeve – the FLip mutation known as F456L. This mutation is kind of a big deal because it changes the way the virus behaves.
Virologist and researcher Stuart Turville, an associate professor at the University of New South Wales in Sydney, characterizes the EG.5 variant as "somewhat more adaptable" and "aggressive" when compared to its counterparts. It appears to possess an enhanced ability to evade the antibodies generated by vaccines, allowing it to navigate more effectively in their presence.
The EG.5 variant is spreading rapidly across the world, it has been reported in 51 countries. It is believed to be highly transmissible and has the ability to evade immunity, making it a variant of interest that needs to be monitored closely.
The FLip Mutation - A Molecular Intrigue
FLip mutation is a double amino acid substitution, which means this mutation switches the positions of two amino acids on the spike protein labelled F and L (F stands for Phenylalanine, and L stands for Leucine). This seemingly minor change is significant. It alters the spike protein's structure, enhancing its binding affinity to ACE2 receptors on human cells. This mutation is also believed to improve the immune escape abilities of the virus and thought to increase the contagion capacity of the virus. In simpler terms, EG.5 has figured out how to unlock our cells more effectively, facilitating infection.
Its subvariant, EG.5.1 bears an additional spike mutation known as Q52H (Q stands for Glutamine and H stands for Histidine; So, the Q52H mutation involves a change from glutamine to histidine at position 52 in the spike protein). While the precise role of Q52H remains elusive, there are indications that it enhances the subvariant's transmission potency. This is evident from EG.5.1's rapid rise in prevalence, surpassing its parent strain.
Why SARS-CoV-2 is constantly mutating?
Viruses naturally mutate over time as part of their survival strategy. SARS-CoV-2 is constantly replicating, and each time a replication occurs, there is a small chance that the genetic code could change (mutate). Mutations in SARS-CoV-2 can also occur due to external factors such as exposure to monoclonal antibodies or the immune system. In this way, viruses adapt to the selection pressure. Some mutations provide a survival advantage, and if that mutated version becomes the dominant strain, it can lead to the emergence of new variants.
The FLiP mutations observed in EG.5 are likely consequence of the widespread use of monoclonal antibodies to treat COVID-19. Monoclonal antibodies target specific regions of the spike protein. In response, the virus may evolve to evade these antibodies, leading to mutations like FLip that alter the spike protein's structure, making it less recognizable to the immune system. The theory is that the mutations are a result of the virus evolving to evade the antibodies.
Symptoms-What to Expect?
Symptomatically, EG.5 doesn't appear to be a game-changer. It tends to infect the upper respiratory tract, with classical COVID-19 symptoms: cough, fever, fatigue, and body aches. The severity can vary from mild to moderate, much like previous variants.
Is EG.5 a Cause for Significant Concern?
The WHO currently assesses the public health risk posed by EG.5 as "low." Therefore, for the general population, there shouldn't be heightened alarm.
However, it's a vital reminder of the potential risks, particularly for those segments of the population most susceptible to severe COVID-19, such as the elderly and individuals with underlying medical conditions.
Will existing vaccines protect against EG.5?
As of now, a significant portion of the population has acquired immunity through a combination of vaccination and prior infection. The initial mRNA vaccines, such as Pfizer-BioNTech and Moderna, were formulated to confer immunity against the original SARS-CoV-2 strain. Subsequently, multiple booster doses were developed, including a bivalent booster to enhance protection against the BA.4 and BA.5 Omicron subvariants. The effectiveness of these vaccines and boosters against EG.5 is an ongoing area of research.
Mandy Cohen, CDC Director, has emphasized that the virus remains susceptible to our vaccines, responsive to our medications, and detectable through testing. Our arsenal of tools remains effective as the virus evolves.
Furthermore, it's important to note that antiviral medications like nirmatrelvir/ritonavir (Paxlovid) continue to demonstrate their effectiveness in mitigating severe symptoms and preventing older and vulnerable populations from progressing to severe disease.
Are there vaccines to target EG.5 variant ?
A new COVID-19 vaccine will soon hit the market, Pfizer, Moderna, and Novavax are all developing versions aimed at Omicron offshoot XBB 1.5, which is closely related to EG.5's ancestor, XBB.1.9.2. The new vaccine won't be an exact match for EG.5. However, early clinical trials show that Moderna’s new vaccine shot will effectively target both the EG.5 and FL 1.5.1 subvariants. The new vaccine will roll out in the fall, it will be a valuable tool to strengthen immunity and adapt to the evolving nature of the virus.
Watch this small video, if you’re curious to know how vaccines work.
Is Masking Up Again Necessary?
While current case numbers may not be as alarming as previous surges, individuals in high-risk groups should contemplate the benefits of wearing masks and maintaining some level of social distancing. Available research studies clearly indicate that masks are effective in reducing the spread of COVID-19.
Concluding Thoughts
As we navigate the ever-evolving landscape of COVID-19 variants, EG.5 stands as a reminder of the virus's adaptability. While it may not be the headline-grabbing Omicron, EG.5 brings its own set of unique characteristics and challenges.
This situation serves as a vital reminder that COVID-19 remains a persistent threat—one that still carries substantial risks. In this ongoing journey, our collective commitment to vaccination, vigilance, and adaptability remains unwavering.
Together, we've proven our resilience, and together, we'll continue to navigate this challenging path with resolve and unity.