Recent reviews have highlighted the unpredictability and complexity of immune interference when multivalent conjugate vaccines are co-administered with other pediatric vaccines. It has become evident that the likelihood of immune interference (in response to conjugated- or co-administered antigens) increases in proportional to the number of glyco-conjugates (valencies) and dosages of carrier proteins. There are many kinds of carrier proteins: tetanus toxoid (TT), diphtheria toxoid (DT), CRM197 (non-toxic variant of DT), OMP (complex outer-membrane protein mixture from Neisseria meningitidis) and non-typeable Hemophilus influenza-derived protein D. Among them, TT is a more potent inducer of T-helper immunity, but carrier-induced-epitopic suppression (dose-dependent carrier antibody and carrier B cell dominance) may occur with TT. In comparison, DT and CRM197 are weaker B-cell immunogens, but apparently trigger more T-regulatory mechanism. Recent pediatric studies of PCV13 co-administered with DTaP vaccines showed 6B GMT (geometric mean titer) to be somewhat reduced compared to the results with PCV13 alone.
Similar to children, adults frequently visit outpatient clinics to get two or more kinds of vaccines at the same time: pneumococcal vaccine, influenza vaccine, Td (diphtheria and tetanus) vaccine, HPV (human papilloma virus) vaccine, meningococcal vaccine, zoster vaccine, etc. PCV13 has limited co-administration information for adjuvanted influenza vaccine.
This study is designed to evaluate the immunogenicity and safety of PCV13 and MF59-adjuvanted influenza vaccine (Fluad) after concomitant administration in adults aged 60 years or older.