The BA.2 subvariant of Omicron has produced more mutated offshoots, according to the Centers for Disease Control (CDC), which are gaining a foothold in the United States. While BA.2 is still the dominant variant in the US, BA.2.12.1 now accounts for about one in five new cases nationwide, the health agency said.
At least 21 viral progeny of the BA.2 have been reported worldwide DailyExpertNews reported. But other than BA.2.12.1, other mutations are of little significance.
The CDC data shows that BA.2.12.1 caused 19 percent of new cases in the US last week, up from 11 percent a week earlier and seven percent a week earlier.
How fast is the new subvariant spreading?
The BA.2 and BA.2.12.1 together accounted for an estimated 93 percent of new COVID-19 cases in the US last week, according to CDC.
The seven-day moving average of U.S. COVID cases stood at 34,972 on April 16, up 23.4 percent from a week earlier.
Overall, cases in the US have fallen sharply since hitting record levels in January, but COVID-19 infections have increased in recent weeks, particularly in northeastern states such as New York and Connecticut.
NBC reported that the latest variant is 23 to 27 percent more transferable than BA.2. However, there is currently no evidence to suggest that BA.2.12.1 causes more serious disease, the report said.
A resurgence of COVID-19 cases in parts of Asia and Europe has raised concerns that a new wave could follow in the US.
What distinguishes BA.2.12.1 from BA.2?
According to Trevor Bedford, an epidemiologist and genome scientist at the University of Washington School of Public Health, B.2.12.1 has peak mutations S704L and L452Q on top of BA.2 background.
Here’s the one to look at on the basis of mutations only, B.2.12.1 with spike mutations S704L and L452Q on top of BA.2 background. Previously, L452R was found to play an important role in promoting the spread of Delta and also showed up in Epsilon and Lambda. 6/17
— Trevor Bedford (@trvrb) Apr 18, 2022
He further said on Twitter that L452R previously appeared to have played an important role in promoting the spread of Delta and also showed up in Epsilon and Lambda.
“We are seeing logistic growth of 0.06 per day in NY (New York) and 0.11 per day in MA (Massachusetts). This is comparable in magnitude to the perceived advantage of BA.2 over BA.1,” he said in another tweet.
Warning for new sublines from Omicron
The New York State Department of Health warned city residents about the new sublines last week, warning that they were spreading about 25 percent faster than BA.2 and were causing Covid-19 cases and hospitalizations to increase.
It also urged New Yorkers to “act quickly” to consider wearing masks, getting booster vaccine doses, getting tested if they had symptoms and seeking treatment if infected.