YouThe World Health Organization (WHO), in May 2021 announced that the key variants of SARSCoV-2, which causes COVID-19, would receive names from the Greek alphabet. This will allow people all over the globe to have a non-stigmatizing and easy way to discuss them. (Before, and often problematically variants were called by different names depending on the location they were discovered. This system gave rise to popular names such as Omicron, Delta and Alpha.
After Omicron’s detection in 2021, variations began to sound more technical with names such as BA.2, BA.2.12.13, BA.4, BA.5, BA.2.75, and most recently BA.2.75. Why all these complex names when there’s still no variant known as Pi?
SARS-CoV-2 has had many variants. Since the WHO does not assign alphabetical names to concern variants that differ significantly from those of previous years, it is clear that there were far more SARS variants. “At the time Omicron was emerging, there were hundreds of sublineages of Delta that we were tracking,” explains Maria Van Kerkhove, the WHO’s technical lead for COVID-19. Compared to those, Omicron represented a drastic shift in the virus’ evolution, with a “substantial” number of mutations, Van Kerkhove says. We now know that Omicron was more contagious than Delta, but less severe.
While there are differences between BA.2, BA.4, BA.5, and the rest of the Omicron subvariants, they’re all fairly similar to each other and the original Omicron strain. That’s why they’re considered descendants of Omicron rather than their own distinct variants with different Greek names to match, Van Kerkhove says.
However, some experts feel that this system should be updated. Trevor Bedford is a professor at Fred Hutchinson Cancer Center Seattle in the vaccine-infectious disease division. He believes it would be more effective to name significant subvariants their own names, at least in public communication. When you say “‘Omicron subvariant BA.2.12.1,’ people tune out,” Bedford says.
The evolutionary jump from Delta to Omicron was large, and the virus may not change that dramatically again for years—if ever, Bedford says. According to Bedford, the bar should be lower for new names being assigned. BA.2 is about 30% less transmissible that the Omicron strain. He notes this as a significant shift. BA.5, currently the US tormentor, appears to be the most contagious.
“If you have a variant that is driving a sizable epidemic in multiple places throughout the world,” Bedford says, “it’s easy to give these a label and would help with everyone understanding what’s going on.”
Van Kerkhove stresses that the WHO still considers and treats Omicron relatives as variants of concern, even if they haven’t been assigned new names.
She adds that scientists around the world continue to monitor the virus’ evolution—but that’s getting increasingly because testing and surveillance efforts have fallen by the wayside as many countries relax pandemic precautions and home testing grows more popular. But that doesn’t mean the virus has stopped mutating. Van Kerkhove points out that there were over 5.7 million global cases last week. Widespread transmission means not only that lots of people will get sick and potentially die, but also that the virus will have chances to keep mutating—perhaps into yet more gradations of Omicron, or perhaps into a variant different enough to earn the label of Pi.
“The virus is under pressure to change,” Van Kerkhove says. “We should be prepared for subtle changes…but we [also] have to be prepared for a completely different virus.”
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