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...