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...