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...