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...