The omicron lineage of COVID-19 has been dominant in Minnesota since before Christmas 2021, but another group of subvariants is soon expected to replace the current dominant strain.
According to the latest wastewater data from the Metropolitan Council, the most prevalent strain of coronavirus from samples tested May 24-30 was omicron subvariant BA.2.12.1 at 64%, which is up from 57% the previous week.
Meanwhile, omicron subvariants BA.4 and BA.5 more than doubled from 11% of samples taken May 17-23 to 23% in the latest reporting period, and that is expected to continue to climb in the weeks ahead.
"BA.4 and BA.5 are expected to replace BA.2.12.1 as the dominant variants in Metro Plant wastewater in the coming weeks," the Met Council announced Friday.
The CDC has not expressed concern that BA.4 and BA.5 cause more serious illness than previous omicron types, though they are extremely transmissible.
"Those are hyper-contagious," said Dr. Gregory Poland, head of Mayo Clinic's Vaccine Research Group, in a podcast recorded May 13. Both omicron family members (BA.4 and BA.5) are known, just like other omicron subvariants, to escape vaccine and natural immunity.
"BA.4 and BA.5 escape – not entirely, but very efficiently – that immunity," said Poland, adding that he believes people not wearing masks and failing to stay up to date with booster shots are leading causes for omicron's continuous evolution.
According to the Minnesota Department of Health, 43.9% of Minnesota's age 5+ population is up to date with vaccine doses. But that percentage is skewed due to 84% of the age 65+ population being up to date, while that percentages drop with age.
- Ages 5-11: 15% are up to date
- Ages 12-15: 24% are up to date
- Ages 16-17: 31% are up to date
- Ages 18-49: 39% are up to date
- Ages 50-64: 57% are up to date
- Ages 65+: 84% are up to date
Overall, the amount virus detected in the wastewater is lower now than it was in mid-May, and nowhere near the record levels during the first omicron (BA.1) wave in December and January.
The Met Council serves about 2 million people in the Twin Cities metro.