The world has been witnessing the worst spike in COVID-19 cases since the pandemic first began over two years ago. Over two million COVID-19 cases were added globally yesterday, more than double the number of COVID-19 cases seen during the height of the Delta wave in 2021.
The surge in infections is led by the newfound Omicron variant, which has managed to rapidly spread all across the world in a surprisingly short amount of time. But the Omicron variant is not the only variant causing infections. The Delta variant of the SARS CoV-2 virus, which still had holdouts in many regions of the world, has also been contributing to the new wave of the pandemic as people engaged in social mixing during the holiday and winter season.
Another variant that has caught the attention of some is the 'IHU variant' of COVID-19 which was found in France in mid-November. While the variant has only caused 12 identifiable cases, its large number of mutations has caught the attention of news organisations.
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Here’s how the three variants stack up
Variant properties
The Delta variant was first identified in late 2020 in India. The variant or the B.1.617.2 lineage was found to have 13 genomic mutations, of which nine were present on the spike protein of the virus. The spike protein of the virus is the part of the virus that is responsible for binding with and thereafter infecting human cells.
Of these nine mutations, four were of particular concern as they indicated that the variant was more easily transmissible, had greater cell level infectivity, and was better at evading the human immune response from vaccines and previous infections. The B.1.617.2 lineage was declared a variant of concern by the World Health Organisation due to its mutations.
The Omicron variant was first identified by South Africa in November after a number of cases of COVID-19 were detected in asymptomatic individuals. Through genomic sequencing, it was determined that the Omicron variant possessed a total of 50 mutations in its genetic structure, of which a concerning 36 were on the spike protein alone.
The B.1.1.529 lineage has now caused over 200,000 cases (that have been genomically identified, the real number of cases is potentially much higher) in just a few weeks since it was identified. Due to its heavily mutated genomic structure, and the pace at which it spread, the variant was almost immediately designated as a variant of concern by the WHO.
‘IHU Variant’ or the B.1.640.2 lineage of SARS CoV-2 has been identified in 12 cases so far near Marseilles but has not been seen in other countries or taken up for investigation by the World Health Organisation. The variant is thought to be linked to travel to Cameroon, with Cameroon or France being possible origins for the variant.
What has caught the attention of many is the fact that just like the Omicron variant, this lineage of SARS CoV-2 has a large number of mutations. The variant has been found to have 46 mutations, of which 14 are present on its spike protein.
Transmissibility, virulence, and vaccine efficacy
The transmissibility of a virus refers to how easily it can transfer from one person to the next. The virulence of a virus refers to the ability of the virus to damage or harm the host. Vaccine efficacy is the percentage reduction of a disease taking hold in a group of people who received a vaccination shot during a clinical trial.
How do three variants compare in this regard?
According to the WHO, the Delta variant had higher transmissibility and virulence than the original variant of the SARS CoV-2. Scientists in the UK estimated that the Delta variant was somewhere around 2x as much transmissible as the original strain that first emerged in 2019, and around 40-60 percent more transmissible than the previously dominant Alpha variant.
The Centers for Disease Control and Prevention highlighted in one of its reports that the reproduction number or R0 of the Delta variant was somewhere between 5-9, compared to 2-3 for the original virus and 4-5 of the Alpha variant. Additionally, even fully vaccinated individuals could spread the variant to other individuals.
While data is varied due to a variety of external factors, it is estimated that the risk of hospitalisation was 2x as much, the risk of ICU intervention nearly 3x as much, and the risk of death was 2x much in COVID-19 cases caused by the Delta variant when compared to other variants.
Again, while figures vary from study to study, it was found that on the whole vaccines were less effective in preventing the Delta variant from causing COVID-19, but still retained protection against more severe symptoms in most cases.
Information about the Omicron variant is still emerging and while it cannot compare 1-to-1 with the Delta variant due to a variety of external factors, scientists have estimated through preliminary findings that the Omicron variant is almost 4x as transmissible as the Delta variant.
While it took several months for the Delta variant to spread over the world and cause the resurgence of a new wave of the pandemic, the Omicron variant has managed to do the same within weeks. The R0 number of the new heavily mutated variant is estimated to be as high as 10.
While the Omicron variant is significantly more transmissible than Delta, it is thankfully much less severe as well. Early data indicates that the variant’s risk of hospitalisation is around 29 percent less than previous variants. But at the same time, new research also indicates that the Omicron variant is much more adept at bypassing the immune response of the human body elicited by both previous infections as well as vaccines.
Not much is known about the IHU variant as it has only been detected in 12 individuals. While the variant does contain the same genes as some of the other variants of concern, which give it higher transmissibility and evasion from antibodies, it has not spread to any significant geographical region.
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Considering that the variant was found before the Omicron variant, and yet its case numbers are so few, it can be assumed that the variant is neither as transmissible nor as adept at evasion as the Omicron variant. Just the presence of a large number of mutations does not predicate the danger of a variant alone. The B.1.640.2 lineage has had its time and at this point, it seems extremely unlikely that it can outcompete against the Omicron variant.
