New “Stealth” Omicron Subvariant Emerges Internationally

by Lance Daley

            A new “stealth” Omicron subvariant has emerged nationally, and it is rapidly spreading throughout major portions of Europe, Asia, and Africa. The new subvariant, formally called BA.2 Omicron, has been dubbed “stealth” Omicron due to its inability to be correctly identified by RT-PCR testing.¹ Testing has incorrectly identified the new subvariant as the Delta variant that swept through the U.S. during 2021. In comparison to the original Omicron variant, BA.2 Omicron has accumulated about 30 different mutations that could make it even more transmissible than the original variant according to Nick Loman, professor of microbial genomics and bioinformatics at the University of Birmingham.² Currently, BA.2 Omicron only makes up about 8% of cases in the US (represented in orange on the frequency graph above), but the rapid onset of the virus internationally may indicate that the U.S. will face a similar fate soon.³

            Given the genetic similarity between the subvariants, it’s possible that antibodies produced from infection with the original Omicron variant or from a booster shot may be able to recognize the new subvariant and help fight infection. If the BA.2 subvariant is as infectious or more infectious than the original Omicron variant, a moderate to high number of cases will likely persist for some time but could continually decrease as more people become infected and gain immunity.⁴ A positive in the emergence of the new subvariant is its mild symptoms and low death rate thus far, similar to the original Omicron variant. Contracting either of these Omicron variants may provide widespread immunity at a much smaller price than prior variants such as the previously mentioned Delta variant that had a higher mortality rate.⁴ More research needs to be conducted on the new subvariant to obtain a better idea of how it compares to past COVID-19 mutants. It’s important to note, however, that there is always potential for the virus to mutate further, resulting in another variant with a new and unique set of characteristics. If the new subvariant is even more transmissible than Omicron, greater spread will provide more opportunities for the virus to acquire random mutations that could allow it to escape current immunity acquired from previous infection and vaccinations. It will be intriguing over the coming weeks to watch the development of the new subvariant alongside the original Omicron variant that is still circulating in the U.S. and around the world.

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References

1. Garcia, Andrea. “What Is the BA.2 or ‘Stealth’ Omicron Subvariant?” American Medical Association, 8 Feb. 2022, https://www.ama-assn.org/delivering-care/public-health/what-ba2-or-stealth-omicron-subvariant.
2. Sample, Ian, et al. “How Worried Should We Be about the New Omicron Subvariant? – Podcast.” The Guardian, Guardian News and Media, 8 Feb. 2022, https://www.theguardian.com/science/audio/2022/feb/08/how-worried-should-we-be-about-the-new-omicron-subvariant-podcast.
3. “Genomic Epidemiology of Novel Coronavirus – Global Subsampling.” Nextstrain, GISAID, Feb. 2022, https://nextstrain.org/ncov/gisaid/global.
4. “CDC Covid Data Tracker.” Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, Feb. 2022, https://covid.cdc.gov/covid-data-tracker/#datatracker-home.