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...