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...