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...