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...