Omicron Subvariant BA.2 Now Accounts For Nearly 25% Of New U.S. Covid Cases Being Sequenced
16.03.2022 - 08:33
/ deadline.com
In recent weeks, there have been frequent reports about the rise of the more transmissible Omicron subvariant BA.2 around the world. BA.2 now makes up nearly all the new cases in Denmark, the U.K., Switzerland, Sweden, India, Belgium, Norway, South Africa, The Philippines, Hong Kong and many more regions.
Throughout the first few weeks of the year, however, as it spread rapidly abroad, BA.2 did not see significant growth in the United States. No longer.
In the second and third weeks of March, the percentage of new U.S. cases sequenced that were attributed to BA.2 was nearly 1 in 4, or 23%. That, per data from Covariants.org, which pulls worldwide data on the genomically-sequenced samples submitted to the GISAID data-sharing hub. In fact, since late January, identified cases of BA.2 have doubled (and sometimes tripled) every two weeks in the U.S.
The first identified cases of BA.2 in the United States appeared at roughly the same time as they did in the U.K. and Denmark: late November & early December 2021. But from that period through mid February, BA.2 made little headway in the U.S., accounting for just 3% of all sequenced cases in the country by the 21st, per Covariants.org.
But during the same timeframe, the percentage of sequences attributable to BA.2 in the U.K. grew to 34%. By February 21 in Denmark, the variant’s conquest was nearly complete; It accounted for 95% of all sequences.
A late January report from the Statens Serum Institut, which operates under the auspices of the Danish Ministry of Health, found that “BA.2 may be approx. 30% more transmissible than BA.1 (the original Omicron).” Some analyses since then have claimed the variant’s transmissibility advantage is even higher.
The good news is that the Omicron