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...