This story has been updated to include the confirmation of BA.2 cases in North Texas.
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. 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.
One of the early systems for differentiating omicron from previous variants is a PCR test that looks for three different genomic targets, he said. BA.1 has a mutation at the site of one of the targets, causing that specific target to fail. BA.2 does not have that mutation, so it can’t be differentiated from delta in the same way.
There’s no current evidence to suggest that BA.2 causes more severe illness than BA.1, Long said. Experts are watching to see whether BA.2 is any better at evading the COVID-19 vaccine than its fellow omicron sub-lineage.