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...