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...