#17,914
After meandering for nearly six months with no clear-cut leader - and often > 24 variants co-circulating in the United States (see Aug 2023 Viral Anarchy) - over the past 2 months we've seen the impressive rise of the SARS-COV-2 JN.1 variant, going from obscurity to full dominance in a matter of weeks.
While it is difficult to make direct comparisons due to changes in testing and reporting over the past couple of years, JN.1 appears to be the most most dominant variant we've seen to date. BA.2 topped out at 86% in 2022 and XBB.1.5 just over 90% a year ago.
We've also gone from 24-30 variants circulating at detectable levels to now just 9, with only one of JN.1's competitors (HV.1) cracking a 1% share. This is a 30-fold decrease in HV.1's share since November.
The history with dominant COVID variants is they rarely last more than 6 months at the top, but we'll have to wait to see how JN.1 fares.
It is also worth noting that the CDC's JN.1 designation undoubtedly encompasses a number of minor offshoot variants aggregated under one label. So far, JN.1 has shown no signs of being more severe than earlier Omicron variants, but it is more immune evasive (see Sato Lab Preprint: Virological characteristics of the SARS-CoV-2 JN.1 variant).
The good news is, it appears that the updated vaccine released last fall provides added protection against this variant (see CDC COVID Vaccine Effectiveness Update). The not-as-good news is that relatively few people have taken advantage of this updated vaccine.
