The United Kingdom Health Security Agency has formally designated a sub-variant of the COVID-19 Omicron strain as a "variant under investigation."
While other previously alarming new variants have had little effect, and details remain unknown, early indications suggest that BA.2 is spreading even in countries where the original Omicron lineage, BA.1, is dominant.
This new VUI has been dubbed "Stealth Omicron" by some health experts due to its apparent ability to elude detection better than its predecessor.
The UKHSA reported the highest number of confirmed cases in London, noting that the original Omicron variant continues to dominate in the UK.
BA.2 appears to have a faster growth rate than its viral predecessor, though further analysis is required, the UKHSA said.
Whereas Omicron quickly displaced Delta following its introduction in the United Kingdom, BA.2 has yet to surpass Omicron, which accounts for the vast majority of cases.
Since November 17, a total of 8,040 BA.2 sequences have been uploaded to the global variant database Gisaid.
BA.2 now accounts for nearly half of the test samples sequenced in Denmark, a country whose COVID-19 policies are frequently compared to those of the United States.
According to data from Statens Serum Institut under the auspices of the Danish Ministry of Health, the sub-lineage accounted for 20% of all COVID-19 cases in Denmark in the final week of December.
By the second week of January, its share had increased to approximately 45%.
According to an HSA report, the new version of Omicron was first detected in the UK on December 6, 2021. To date, there have been 426 confirmed cases, with the greatest concentration centered around London (146) .
There are conflicting reports regarding the origins of BA.2, with some pointing to South Africa, others to India, and still others to the Philippines.
Meanwhile, BA.2 has also been discovered in the United States, according to Sinclair Broadcasting's KOMO News station in Seattle, which reported that the Washington State Health Department confirmed two cases of the sub-variant were "discovered earlier this month."
"There have been fewer than 100 confirmed cases of BA.2 in the U.S. thus far," Washington health department representative Shelby Anderson said.
At least three cases have been identified at Houston's Methodist Hospital, where robust genomic sequencing is available.
However, according to one anonymous Biden administration official quoted in Monday's Washington Post, "there is concern about the omicron BA.2 variant."
Due to the increase in overseas cases, the official stated that the U.S. is preparing and "paying close attention to the BA.2 variant."
