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...