BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Ba.2.86

How is Omicron still a problem?

Covid-19 under a microscope

 

Allow me to take you back to the early days of the Covid-19 pandemic. Alpha, and Delta were the primary variants.

And then Omicron stumbled in, and unlike the others, never left.

Unlike the others, who had viciously ensnared others to their deaths, Omicron was more akin to a hard cold, or the flu. Whilst it shared flagship symptoms like parosmia (loss of smell/taste) and other respiratory symptoms, they resulted in less hospitalizations. In addition, we were going stir crazy and had started to unlock the lockdown. 

And Omicron, unlike the others, was a rapidly evolving virus, one variant one second and another the next. The rapid mutations in the epitopes (the spike protein that the immune system uses to distinguish it from other viruses) made vaccines, which are designed to emulate the epitopes so the body can recognize it (hence the potential fever- your body is learning the epitope’s shape so it can catch the real thing faster), next to impossible to settle on. Trying to get a working vaccine for it was like trying to hold a tiny fish in the rain- it just kept slipping away. 

And now again, descendants of Omicron are dominant again.

HV.1 is a descendant of Eris (EG.5) but isn’t really that different from Eris. Vaccines that are designed to target XBB (another offshoot) still work on both of them. HV.1 is only dominant for minor mutations, as vaccines still work.

The real worry is BA.2.86, which has been determined to evade the immune system. It, in comparison to say, EG.5.1 or XBB.1.5, resulted in a lower concentration of neutralizing antibodies, meaning one infected would be infected for longer.

Its descendant, JN.1 might be even better at it. It can be transmitted at low levels due to its highly mutated spike protein, and still evades the humoral response more effectively than its predecessor.

I, for one, think that Omicron isn’t going away. It mutates too quickly to truly be caught. But I think a monovalent vaccine is possible per each set of dominant strains. And to that, I mean it will likely become another vaccine to get annually in the fall.

The “Slow but Steady” Increase of yet Another COVID-19 Variant: What are the Implications?

Globally, there has been a slow but steady increase in the proportion of BA.2.86 reported, with its global prevalence at 8.9% in epidemiological week 44” (WHO)

Another variant? Since the beginning of the epidemic, we have seen a few strains of COVID-19 arise, notably the Omicron, Delta, and Alpha variants. You may ask, how do these mutations keep on materializing?

Like all viruses, SARS-CoV-2 — the virus responsible for COVID-19 — goes under, and will continue to go under, several mutations.

File:SARS-CoV-2 without background.pngAs a coronavirus, SARS-CoV-2 uses protein spikes (visualization on right) that fit into cellular receptors, in order to infiltrate our cells. Upon entry of the virus, the invaded cell begins to translate the viral RNA into viral proteins, which leads to the production of new viral genomes. According to Akiko Awasaki, PhD, this is where mutations often arise, stating that, “When viruses enter the host cells and replicate and make copies of their genomes, they inevitably introduce some errors into the code.” While these introduced errors may be inconsequential, they can also be of benefit to the virus, increasing contagiousness. These successful mutations may change how the virus behaves in the future, becoming the foundations of new evolutionary steps.

As we learned in AP Bio, the sequence of amino acids plays a heavy role in the primary structure of the spike protein. When the sequence is altered, hydrogen bonds will be corrupted or created, affecting the stability of the secondary structures like alpha helices and beta pleated sheets. This changes will in turn affect the tertiary structure, ultimately morphing the three-dimensional shape of the spike protein.

Given this knowledge of how SARS-CoV-2 invades cells, and how it may lead to evolution and mutation, what is the significance of this newest variant, and how can it be fought?

BA.2.86 was discovered over the summer with cases from Denmark, Israel, the United Kingdom, and the United States. Later on, it spread to various countries all over the globe, being discovered in wastewater in countries such as Spain and Thailand. As weeks passed, the new strain did not seem to pose a threat compared to its predecessors. However, months later, BA.2.86 on the rise. On November 11th, the CDC estimated that 3.0% of cases came from BA.2.86. November 28th’s estimate, 8.9%, is shockingly almost triple of the earlier estimate just two weeks prior. This is apparently garnering the strain some sort of reputation, now being labelled a “variant of interest” by the World Health Organization.

While the percentage may seem scary, the rise of the strain has not brought a disproportionate growth in infections or hospitalizations. Rather than posing new or threatening danger, it seems to be much better adept to escaping our bodies’ defense systems. The improved ability to slip past antibodies, compared to previous variants, likely comes from its large number of mutations, 30, on its spike protein. Antibodies, which serve to fight these invaders, may find difficulty recognizing and defeating the new strain.

Due to the strain only taking the notice of researchers recently, there are still many things to be uncovered. Some researchers have affirmed their support in newer vaccines against BA.2.86 and future variants. As always, it is best to wear masks when necessary, wash your hands, quarantine if you are experiencing symptoms, and receive the latest vaccine.

File:Janssen COVID-19 vaccine (2021) K.jpg

 

 

 

 

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