Colorized scanning electron micrograph of a cell, remoted from a affected person pattern, that's closely contaminated with SARS-CoV-2 virus particles showing in pink. (Photograph courtesy of Nationwide Institute of Allergy and Infectious Ailments’ Built-in Analysis Facility)
Santa Clara County well being officers Tuesday mentioned they've recognized two COVID-19 circumstances of a worrisome sub-lineage of the fast-spreading omicron variant.
Well being officers had little info Tuesday concerning the two circumstances of the sub-lineage, often known as BA.2, and mentioned it’s not but identified whether or not it's extra transmissible or virulent than the dominant omicron sub-lineage, often known as BA.1.
“The BA.2 sub-lineage is far rarer, however has begun to pop up in locations, together with California and Santa Clara County and different locations world wide,” Santa Clara County Deputy Well being Officer Dr. George Han mentioned Tuesday.
Han mentioned it’s unclear how troubling the brand new variant may be, and he had little info to share concerning the two native circumstances.
“The principle factor about this sub-lineage is that as a result of it’s a lot much less frequent, we don’t know a lot about it,” Han mentioned. “Early indications are that it most likely behaves very like the omicron BA.1 sub-lineage, but it surely’s laborious to inform due to the small variety of circumstances to this point.”
In line with the World Well being Group, the omicron variant has 4 lineages often known as B.1.1.529, BA.1, BA.2 and BA.3. Whereas the BA.1 lineage has beforehand been essentially the most dominant, current developments from India, South Africa, the UK and Denmark recommend that BA.2 is growing in proportion, the WHO mentioned.
“Drivers of transmission and different properties of BA.2 are underneath investigation however stay unclear to this point,” the WHO mentioned in a Jan. 21 replace.
BA.2 has been dubbed “stealth omicron” as a result of most Omicron variant sequences embody a deletion within the S gene, which may trigger what scientists name an “S gene goal failure” in PCR checks that has been used to determine variants as omicron. The BA.2 sub-lineage, nonetheless, lacks that S gene deletion, the WHO mentioned, so utilizing that S gene goal failure to determine omicron would possibly miss the BA.2 lineage.
Han mentioned that the BA.2 sub-lineage will be recognized by a full genetic sequencing, which isn't generally accomplished on most virus samples, however was used to determine the Santa Clara County circumstances.
BA.2 additionally has been reported in Washington state and Texas. The Facilities for Illness Management and Prevention and California Division of Public Well being haven't been individually monitoring the sub-lineage publicly.
The California Division of Public Well being mentioned Tuesday that as of Jan. 24 there have been a complete of 11 confirmed BA.2 circumstances within the state.
“New variants will proceed to evolve so long as there are massive pockets of unvaccinated folks,” the division of public well being mentioned in an announcement. “Strengthening our safety in opposition to COVID-19 via vaccination and boosting is extra necessary than ever.”
Denmark’s Staten Serum Institut in Copenhagen final week reported that the proportion of BA.2 circumstances within the nation had risen in simply weeks from 20% to 45%, and instructed the the Washington Put up on Monday it now accounts for 65%.
On Friday, the UK Well being Safety Company designated BA.2 a “variant underneath investigation,” on the idea of “growing numbers of BA.2 sequences recognized each domestically and internationally.”
The Well being Safety Company mentioned a complete of 40 nations have uploaded 8,040 BA.2 sequences since Nov. 17 and it's unknown the place the sub-lineage might have originated. The primary sequences have been submitted from the Philippines, and most samples have been uploaded from Denmark — 6,411. Different nations which have uploaded greater than 100 samples are India (530), Sweden (181), and Singapore (127), the company mentioned.