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...