Lower antibody functionality in middle-aged adults compared to adolescents after primary meningococcal vaccination: Role of IgM

Although protective antibody titers were initiated after primary meningococcal vaccination in middle-aged adults, antibody functionality was significantly lower as compared to that in adolescents. This difference was mainly caused by lower IgM responses. Our results indicate early signs of immune ageing in middle-aged adults, which is important knowledge for the development of future vaccine strategies to better protect elderly persons against infectious diseases.