What We Know About the Omicron Clan of Virus Variants

The global spread of SARS-CoV-2 has spawned a plethora of virus variants, each competing to more efficiently spread and evade the antibodies people generated from past infections and vaccinations. The highly transmissible omicron variant sent daily cases of Covid-19 to new heights early this year and its subvariants continue to evolve, driving fresh outbreaks. That’s challenging the achievement of community protection via so-called herd immunity, prompting the development of updated vaccines as well as testing the public’s tolerance for pandemic-mitigation efforts like booster shots, frequent testing and mask-wearing.

Omicron was first identified in southern Africa late last year when it outcompeted the delta variant. Omicron’s initial iteration, B.1.1.529, is characterized by some 30 mutations in the gene for the spike protein, which gives the coronavirus its crown-like appearance and allows it to invade cells. Changes there can make the pathogen less recognizable to the antibodies the immune system makes in response to vaccination or a case of Covid, increasing the risk of infection in such cases. Over time, subvariants of the original omicron strain have evolved, with the “fittest” superseding earlier versions. Several have been shown to cause different patterns of symptoms and may carry different risks of persistent or “long-haul” symptoms.