As of now, omicron BA.2.86 isn’t on the verge of taking over the world.
Just because it has been added to WHO’s variants under monitoring doesn’t mean it’s spreading faster.
The SARS-CoV-2 omicron variant lineage BA.2.86, also referred to as ‘Pirola’ by ‘Coronavirus hunters’, has been receiving significant media attention.
I am writing this article in response to reports from certain news outlets claiming that BA.2.86 is rapidly spreading across the globe, when in fact, this is not entirely true.
However, the variant remains an intriguing subject of study.
Pirola has not been detected in Denmark for the past week. Why is Denmark significant, you may ask?
It is noteworthy that Denmark is one of the first countries to detect Pirola.
However, what makes Denmark even more intriguing is that it has sustained strict COVID-19 surveillance globally, despite other countries scaling down their efforts.
What’s my point? It’s not true that Pirola is taking over the world like the XBB (and its descendants) are doing. The popularity of Pirola is due to the number of mutations it has. World Health Organization (WHO) has even declared it a variant under monitoring.
Pirola has over 30 mutations in its Spike (S) protein, as compared to its parental lineage BA.2. Omicron BA.2 was the most prevalent lineage in early 2022, and was itself a mutated version of BA.1 (first Omicron).
Moreover, Pirola has over 35 mutations in its S protein, as compared to Kraken (XBB.1.5), which was the dominant variant in 2023 prior to the emergence of Eris in August 2023.
Why is it surprising that there are 30+ mutations? This is what has made Omicron the most prevalent and long-lasting variant of SARS-CoV-2 to date.
When compared to previous variants such as Delta, Omicron has over 30 substitutions that provided it with an evolutionary advantage in terms of immune evasion and transmission.
On immunity
The expected type of immunity for Pirola is solely dependent on T-lymphocytes due to numerous mutations in its whole genome, instead of B-lymphocytes.
The primary role of T-lymphocytes is to participate in cell-mediated defenses, while B-lymphocytes use antibodies and/or memory to provide immune defense.
The process of vaccination is designed to stimulate the creation of targeted antibodies and foster the development of memory B-cells, with the ultimate goal of combating a specific pathogen. It should be noted that this process primarily involves B-lymphocytes, rather than T-lymphocytes.
It is important to note that the activation of T-lymphocyte defense mechanisms takes longer than that of B-lymphocyte defense mechanisms, resulting in a delay in the body’s response to the invading pathogen.
The potential challenge in neutralizing the Pirola variant of XBB stems from the fact that memory cells and antibodies that were previously effective against other variants may struggle to recognize and bind to the altered S protein structure caused by more than 30 amino acid substitutions.
These structural changes impact the most targeted epitope (S protein) for vaccines, making it a significant concern in vaccine development and immunity against the Pirola variant.
On vaccines
The efficacy of the upcoming XBB.1.5 vaccine against Pirola remains uncertain, despite the previous confidence in its ability to protect against Eris.
Scientific literature has yet to provide definitive evidence in support of its effectiveness against Pirola.
Further research and clinical trials are required to determine the potential of the vaccine in mitigating the impact of this pathogen.
The examination of Pirola’s entire genome reveals numerous mutations that must be analyzed in order to determine its virulence and evolutionary advantage.
The greater the number of mutations, the larger the number of variables and permutations that must be taken into account in order to accurately predict its potential.
It is important to note that the presence of numerous mutations in a virus does not necessarily confer an advantage, as certain mutations may lead to a less virulent virus.
As previously stated, to date, only ten confirmed cases from Pirola have been reported as of 25 August 2023.
Pirola is distinguished from Kraken, Eris and FL.1.5, which are dominant sub-lineages in certain regions of the world, by its lack of close relation to the XBB sub-variants (as shown in the opening phylogenetic tree above).
Pirola belongs to a distinct clade that is not closely associated with the XBB clade. These findings suggest a complex evolutionary history for this group of omicron coronaviruses.
Based on current research, there appears to be a low level of confidence in the efficacy of the upcoming vaccine in providing protection against Pirola.
I want to make it clear that Pirola has not shown evidence of increased transmissibility or hospitalizations like EG.1.5.
This is supported by the fact that there have only been 10 confirmed cases of Pirola globally, making the sample size very small.
Conclusion
Based on current understanding, Pirola is not exhibiting the same level of global dominance as observed in the XBB lineage and XBB descendants.
However, researchers are concerned about the numerous mutations present in Pirola. A variant with this many mutations can be unpredictable in terms of its ability to evade the immune system, its transmissibility, and its potential to cause hospitalizations.
Pirola has also surfaced at a time when several SARS-CoV-2 variants are emerging, leading to a rise in hospitalizations.
