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...