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...