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...