And just like that the newest relatives of the omicron family have officially arrived in Minnesota.
Last week, Bring Me The News reported that subvariants known as BA.4 and BA.5, which were first discovered in South Africa, were detected in Twin Cities wastewater. Now they've been identified through genomic sequencing, confirming their presence in Minnesota.
Through May 17, four cases of BA.4 and one case of BA.5 were confirmed through testing. Only one of the five cases was a person living in the Twin Cities metro area.
Preliminary studies focused on BA.2.12.1,, BA.4 and BA.5 have found that all three mutants are capable of infecting a person who is vaccinated and boosted, or has been infected previously by the original omicron virus (BA.1) or the first spinoff, BA.2. All three are believed to more transmissible than BA.2, though there is no indication that they cause more severe disease.
"Those are hyper-contagious," said Dr. Gregory Poland, head of Mayo Clinic's Vaccine Research Group, in a podcast recorded May 13.
"What's driving this," Poland continued, "is people pretending that the pandemic is over and not wearing masks." He added that waning immunity and people failing to stay up to date with booster shots is also helping omicron constantly evolve.
"BA.4 and BA.5 escape – not entirely, but very efficiently – that immunity," said Poland. "We can expect that, just like omicron started in South Africa, we can expect that will come on the heels of these BA.2 subvariants."
The dominant variant in Minnesota is currently BA.2, though wastewater data from the Metropolitan Council indicates that BA.2 is being replaced by BA.2.12.1, of which there have been 131 confirmed cases in Minnesota.
But don't be fooled by there only being five confirmed BA.4/BA.5 cases and 131 BA.2.12.1 in Minnesota. Those numbers are likely far higher but impossible to prove in entirety because more people are testing at home, meaning fewer samples undergo genomic sequencing.
According to Mayo Clinic, wastewater data is the best indicator for what's happening in a given community or state. As of May 16, 56% of wastewater samples tested by the Metropolitan Council were BA.2.12.1, while 32.4% were BA.2. A month ago (on April 20) BA.2 accounted for 80% of wastewater samples and just 10% were BA.2.12.1.
"Because the majority of testing is being done at home, we can no longer tell you accurately about the positivity rate for a given community or a given state like we used to be able to," said Poland.
"And this is problematic. It means that we lose our ability to understand what's called genetic epidemiology — the ability to trace how these variants are moving, how fast they're moving, and whether they're changing and evolving into yet different subvariants or new variants. We've lost that ability now."
Mayo Clinic's advice: mask up and stay up to date with your vaccine doses. You can learn when you're eligible for a third or fourth vaccine dose right here.