Omicron BA.2 overtakes BA.1 as most common SARS-CoV-2 variant in the US
But what does this all mean for us in the coming months?
Another variant? Well, sort of.
There are three related but genetically distinct varieties of the Omicron variant of SARS-CoV-2-- We all remember BA.1 from this winter since it caused a MAJOR spike in cases around the world in December and January. The subvariants are closely related, but there are differences.
Many of the properties of BA.2 appear similar to those of BA.1 in terms of its ability to evade vaccines and its relatively low potential for causing severe disease compared to other variants, such as delta, which caused a lot of morbidity and mortality globally. However, BA.2 appears even more highly transmissible than its sibling and is being compared to measles with regard to its contagion factor.
BA.2 has overtaken BA.1 as the dominant strain of the virus in the US per CDC’s genomic surveillance system. Based on its models, the agency says that BA.2 caused between 51% and 59% of all new infections in the US the week ending March 26, up from an estimated 39% of all new infections the week before.
The hardest-hit region was the Northeast, where BA.2 caused more than 70% of all cases. The South and Mountain West saw the fewest cases. BA.2 caused slightly more than one-third of infections in those regions last week.
What does this all mean for us in light of newly lifted restrictions and changing recommendations? To be candid, we aren’t quite sure. It is possible that BA.2 will cause a spike similar to one seen in Europe—but there are differences between Europe and the US (with regard to mitigation measures, vaccination rates, and proportion of the population previously infected with COVID-19) that hinder the ability to make a direct comparison. Most scientists agree that we’ll likely see a rise in numbers in certain pockets of the country, but it is unlikely that we will see the avalanche of cases seen with BA.1.
Later today, we are going to post to Substack our more detailed perspectives and predictions for COVID-19 trends and whether we might be entering the “endemic” stage of the virus. Be sure to subscribe to check it out!
Sources:
https://www.cidrap.umn.edu/.../study-suggests-ba2-covid...
https://publichealth.jhu.edu/.../here-we-go-again-the-ba2...
https://covid.cdc.gov/covid-data-tracker/...
https://www.npr.org/.../the-more-contagious-ba-2-version...
https://www.ama-assn.org/.../what-ba2-or-stealth-omicron...
https://news.harvard.edu/.../harvard-experts-encouraged.../
What are the implications of this? Is COVID-19 now endemic or is this still considered a pandemic? Let’s discuss!
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