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...