New Covid Variant BA.4.6 Outcompeting Dominant BA.5 Across Swath Of U.S. For First Time
31.08.2022 - 01:41
/ deadline.com
The Centers for Disease Control’s weekly variant proportions data update today offered the clearest indication yet that a new Omicron strain dubbed BA.4.6 may be able to outcompete now-dominant BA.5 in the United States.
While BA.4.6 has been in the U.S. since at least May, it remained below 2% of new cases sequenced until July, when it gradually began to rise, even as BA.5 continued to do the same. As of this week’s CDC reporting, it currently stands at 7.5%. But the real wrinkle comes when the variant proportions are broken out regionally.
In the area defined primarily by California, Arizona and Nevada, BA.4.6 lags behind even BA.4, with shares of 2.8% and 3.3%, respectively. BA.5 in the region stands at 93% and rising.
Compare that to the CDC-grouped region of Nebraska, Iowa, Kansas and Missouri, where BA.4.6 has risen to 17.2% of all new cases sequenced, and BA.5 actually fell for the first time this past week to 78.5%. It peaked at 80% there in the first week of August and has fallen slightly in the three weeks since. During same that time frame BA.4.6 has nearly doubled in those states from 8.7%.
The good news is that in all four of those states Covid numbers are down across the board.
By one analysis of GISAID data, the new Omicron variant has a 16% growth advantage over BA.5, which makes it all the more bizarre that it has beat out BA.5 in some areas of the U.S. while making little progress in others.
The reasons for these region differences are unclear. Los Angeles Public Health Director Barbara Ferrer told the Los Angeles Times last week.
“I don’t know if there’s some relationship to the environment or the weather or particular conditions, including the vaccination status of the residents in those communities, as