related_tweet: the proportion of the population needing resistance varies along with the r0, and not with the serial interval. so, if the r0 never got higher than 2.5, then herd immunity would temporarily be reached once 60% of the population were resistant. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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