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...