THERE WAS A  CROWDSOURCED  VACCINE,   
  THAT COULD  BE CREATED REGIONALLY BY  
    MOST   PHARMACEUTICAL  COMPANIES    
   WITHOUT  MUCH  EFFORT, AND IT  WAS   
   ESTIMATED   THAT   IT   HAD  SAVED   
      TENS      OF      MILLIONS.       
                                        
 BUT IT WAS  NOT OFFICIALLY RECOGNIZED BY 
 THE  WORLD HEALTH ORGANIZATION,  AND  AS 
 SUCH DID  NOT  GIVE WHAT  THE SANCTIONED 
 (AND   UNOBTAINABLE)   ONES   DID:   THE 
 SUBSKIN  CHIP  THAT WOULD  LET YOU ENTER 
      (OR     LEAVE)      CITIES.       
                                        
  AND THAT'S WHY, EVENTUALLY, WE WOULD  
  CREATE  OUR  OWN  CHIPS.  THEY  WERE  
  LARGER THAN THE OFFICIAL ONES, AND A  
    LITTLE   UNSTABLE,  AND   NEEDED    
    MAINTENANCE.  BUT   THEY  WORKED!   
  OR, THEY WOULD WORK TOGETHER WITH  A  
  LITTLE SOMETHING  TO  MAKE THE GUARD  
     LOOK     THE    OTHER    WAY.      
                                      
                                      
                                          
    BUT THE SCANNER SHOWED GREEN, SO...