New Variant Classification

Last week the CDC revised its classifying terminology for SARS-CoV-2 variants.  To have clarity in our thoughts and debates, we must be precise in our language.  Poor decisions often descend from muddled and incomplete understandings.  I know that readers of these posts strive to be current in models of understanding and language, so they will not be caught flatfooted in conversation and reasoning.  That’s why I summarize the essential points here.

There are now three types of SARS-CoV-2 variants: Variants of Interest, Variants of Concern and Variants of High Concern.  I will discuss the definitions, lists of variants and their characteristics in reverse order.

Variants of High Concern.  Variants of high concern are those SARS-CoV-2 variants that cannot be detected by tests, are not treatable by current therapies or for which natural or vaccine induced immunity offers no protection.  Any one of those three criteria is enough to place the variant on the High Concern list.  Scary stuff.  The good news is that there are no variants on this list.  At least not yet.

Variants of Concern.  Variants of Concern have reduced detection by tests, reduced response to therapy, reduced immune protection, greater transmissibility, or more severe disease.  Again, any one of these criteria is enough to land a variant on this list.  The bad news is that the number of variants on this list has exploded since the last time I wrote about it.  In addition to the B.1.1.7 variant first detected in the UK last fall, four other variants have been added to the list:

These Variants of Concern have all been identified in the United States.  The B.1.427/429 Variants of Concern are most prevalent in the western United States, now responsible for more than half of infections in California.  The B.1.1.7 Variant of Concern is most prevalent in New Jersey and Florida, approaching 10% of the new viral infections there.  Click here to view the current numbers and distribution in the United States.  To see worldwide cases of COVID-19 caused by variants, click here.  These maps are updated at least weekly.

Variants of Interest.  Variants of Interest are being watched closely because they have the potential to become Variants of Concern based in the mutations within the variant, even though they don’t fulfill criteria to be a Variant of Concern based on observation.  This may be because the variant is too new or because too few of the instances of the variant exists to make meaningful observations.  The current Variants of Interest and their potential, but not observed, effects are listed below:

Like the Variants of Concern, all the Variants of Interest are currently present in the United States.  

There are a number of other variants which have been identified and named, but which have not yet been classified as a Variant of Interest, Variant of Concern, or Variant of High Concern.  Expect the members of these variant classification lists to change and shift as more becomes known about variants.