Our World In Data - Confirmed Cases In 3 Countries (UK,US, Canada)
#16,527
Barely 60 days after it was first announced (see South African NICD Statement On B.1.1.529 Variant), and after causing a record number of infections over a very short period of time, there are some hopeful signs that the first Omicron wave may be slowing in the UK, the United States, and Canada (see chart above).
All three countries appeared to have reached their peaks in the first 10 days of January, although changes in data collection and reporting, and milder illnesses, may be skewing the picture somewhat.
While case levels remain high, they are no longer climbing like a homesick angel; they have leveled off and have even declined in some regions. Anecdotally, I'm seeing fewer hospitals where I live (central Florida) on Divert or Bypass the past few days, suggesting a drop in patient levels.
As hopeful as these signs are, there are three European nations which reported the arrival of Omicron at roughly the same time as the UK, US and Canada, that are still reporting increasing cases; Denmark, Sweden, and Norway (see chart below).
While it is possible that differences in testing and reporting by these countries may be affecting these trends, there is another possibility worth noting. In the United States, Canada, and the UK the primary Omicron variant being reported is BA.1., which is currently the most commonly reported (>99%) Omicron variant being reported worldwide.
But earlier this week, in Omicron Subvariant BA.2 Now Accounts For Nearly Half Of All Danish Cases, we learned that a different Omicron variant was surging in Denmark. To a lesser extent, we saw similar reports from Norway and Sweden (see Norwegian Institute of Public Health Also Reports A Rapid Increase In Omicron BA.2 Subvariant).
On Friday, just two days after the UK announced their plans to roll back Plan B COVID restrictions, the UKHSA announced that due to rising detections, the Omicron Sublineage BA.2 was Designated as A VUI (Variant Under Investigation).
For now, data is very limited on BA.2. Currently there is no evidence that BA.2 produces more severe illness, or poses any greater threat than BA.1. But it does appear to be able to compete successfully with BA.1 in parts of Scandinavia, and may even be more transmissible.
The $64 question - one that remains unanswered right now - is whether infection with Omicron BA.1 conveys reasonably long-lasting immunity against BA.2. If it does, the BA.2 may be a problem reserved for next fall or winter. If it doesn't, then our current plateauing of cases here in the United States may not last very long.
For what its worth, there are reports in the Danish media of an interview with SSI Chief researcher Anders Fomsgaard, where he suggests that infection with BA.1 may provide only limited protection against reinfection with BA.2. But this appears to be preliminary information.
Which is why we'll be watching Denmark, Norway, and Sweden - and potentially the UK - to see if they experience a second Omicron wave, propelled by BA.2.
Even if BA.2 turns out to be a flash in the pan, SARS-CoV-2 continues to evolve, and additional variants are almost certain to emerge to challenge herd immunity.
Which is why, while I'm somewhat encouraged by the recent trends here in the US, UK, and Canada, I'm not putting my N95s back into storage anytime soon.
