salivary antibody levels in adolescents in response to a meningococcal serogroup c conjugate booster vaccination nine years after priming systemically induced local immunity and saliva as potential surveillance tool background in several countries largescale immunization of children and young adults with meningococcal serogroup c menc conjugate vaccines has induced longstanding herd protection salivary antibodies may play an important role in mucosal protection against meningococcal acquisition and carriageaim to investigate antibody levels in preadolescents primed 9 years earlier with a single dose of mencpolysaccharide tetanus toxoid conjugated menctt vaccine and the response to a booster vaccination with special focus on agerelated differences and the relation between salivary and serum antibody levelsmethods nine years after priming healthy 10 n91 12 n91 and 15yearolds n86 received a menctt booster vaccination saliva and serum samples were collected prior to and 1 month and 1 year after vaccination mencpolysaccharidemencpsspecific antibody levels were measured using a fluorescentbeadbased multiplex immunoassayresults before the booster mencpsspecific igg and iga levels in saliva and serum were low and correlated with age at priming the booster induced a marked increase in salivary mencpsspecific igg 200fold but also in iga 10fold one year after the booster salivary igg and iga had remained above prebooster levels in all age groups 20fold and 3fold respectively with persistence of highest levels in the 15yearolds mencpsspecific igg and iga levels in saliva strongly correlated with the levels in serumconclusion parenteral menctt booster vaccination induces a clear increase in salivary mencpsspecific igg and iga levels and persistence of highest levels correlates with age the strong correlation between serum and salivary antibody levels indicate that saliva may offer an easy and reliable tool for future antibody surveillance