The speed at which these variants are turning up and spreading makes it feel like we're watching water circling the drain and it's getting faster as the unvaccinated and uninfected population level in the tub drops.

We heard about Omicron BA.2 last week. This from today's Dallas Morning News

Researchers confirmed two cases of BA.2, a sub-lineage of the omicron variant, through sequencing at the University of Texas Southwestern on Thursday.

Scientists discovered the sub-lineage in December, shortly after the original omicron lineage, called BA.1, was identified. Recent spread of the sub-lineage led the U.K. Health Security Agency to designate BA.2 as “under investigation.”

Public health experts are monitoring the strain as it spreads in several European and Asian countries. BA.2 is believed to be more transmissible than BA.1, but not much else is known about the variant.

In Denmark, BA.2 jumped from 20% of COVID-19 cases in the last week of December to 45% of cases in the second week of January, according to Danish public health organization Statens Serum Institut.

Fewer than 100 cases of BA.2 have been reported in the U.S., a mere fraction of the more than 660,000 omicron cases detected in the country in the last week, according to the Centers for Disease Control and Prevention.

While BA.2 has the potential to take over omicron as the dominant variant in the U.S., it’s too early to tell what impact the sub-lineage will have on the pandemic, said Dr. Wesley Long, medical director of diagnostic microbiology at Houston Methodist.

“In the U.S., we have to wait and see what the story is on BA.2 and how it compares to BA.1,” he said. “It’s worth keeping an eye on right now.”

Here’s what experts know so far about the sub-lineage — and what they know about other future COVID-19 variants.

Today we find that it is circulating in at least half of the states in the US.

Here we go again.