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...