The worst-case scenario, while unlikely, is plausible & terrifying: rampant reinfection, increased disease severity (no sign yet but higher viral loads suggest the possibility), & greatly reduced vaccine efficacy against a newly hyper-contagious virus. This is truly scary stuff. https://twitter.com/statnews/status/1342210220186083328

Of course, it's far more likely that this variant—and the others now cropping up—will simply be more transmissible but not cause more severe disease or substantially reduce vaccine effectiveness. But even that scenario—which seems very likely—would be extremely destructive.

It doesn't take much of an increase in R0 to make a tolerable situation catastrophic. The difference between an R0 of 0.9 and an R0 of 1.3 is the difference between a virus being defeated and a virus growing exponentially and uncontrollably.

Some are urging restraint and worried about panic. But looking back on the past nine months of this pandemic, how often have we urged too much restraint and acted too quickly? And how often have we waited too long to react, resulting in enormous outbreaks?