March 2022    
         
         
 
     
  Terms and conditions  
     
  Scientists, journalists, and the general public often use different—if not contradictory—language to talk about the same things. In our third year of the pandemic, language surrounding COVID-19 is still tricky, particularly when it comes to variants.  
     
 
  What’s the difference between
mutations, variants, and strains?		  
 
       
  Short answer: All strains are variants, but not all variants are strains—and they’re both mutations.  
     
  A moving target  
     
 
SARS-CoV-2 illustration
 
 
     
  (iStock.com/MrJub)  
     
 
     
  Last spring, as vaccines rolled out, many of us took a deep (but still masked) breath of relief. Then the delta variant arrived in the United States, followed by omicron. By the time you read this, we may be in the midst of another variant surge.  
     
  Two UChicago Medicine physicians outline what we know so far about the SARS-CoV-2 variants.  
     
 
 
  Variant vigilance  
     
 
     
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What the next variant will be depends on its “fitness landscape.”
 
     
     
     
 
     
  2  
     
 
The CDC sequences primarily severe and fatal cases of COVID-19, but analyzing milder cases may offer more insight into how these viruses mutate.
 
     
     
     
 
     
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While omicron is now the dominant variant in the United States by a wide margin, scientists aren’t yet ready to declare delta down for the count.
 
     
     
 
         
         
    Spotlight    
         
         
 
     
  It’s all Greek  
     
 
name tags
 
 
     
  (iStock.com/miflippo)  
     
 
     
  Have you heard of the B.1.617.2/GK/21A variant? You might know it by its Greek name: delta.  
     
  Scientific names are important for tracking genetic lineages, but they’re difficult for reporting and public discourse. Last year the World Health Organization led the effort to identify a variant nomenclature that was easy to discuss and non-stigmatizing, settling on the Greek alphabet.  
     
  Delta and omicron are considered “variants of concern,” but the World Health Organization also tracks current and former “variants of interest” and “variants under monitoring”—if you were wondering what happened to epsilon through xi.  
     
 
 
  In case you missed it  
     
 
 
 
Webb watch: The James Webb Space Telescope launched at long last.
 
 
Belly swell: Why you shouldn’t ignore your indigestion.
 
 
 
 
 
 
 
     
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