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...