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...