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...