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...