Authors:
Nissen M, Marshall H, Richmond P, Shakib S, Jiang Q, Cooper D, et al.
Authors notes:
Vaccine. 2015;33(15):1846-54.
Keywords:
Staphylococcus aureus, Vaccine, Functional antibodies
Abstract:
Background: Staphylococcus aureus is a common cause of healthcare-acquired morbidity and mortality and increased healthcare resource utilization.
A prophylactic vaccine is being developed that may reduce this disease burden.
Methods: Volunteers in good general health aged 50-85 (n=312) and 18-24 (n=96) years were randomized to receive a single intramuscular dose of one of three dose levels of a non-adjuvanted, 3-antigen S. aureus vaccine (SA3Ag) or placebo.
SA3Ag antigens included capsular polysaccharides 5 and 8 (CP5 and CP8), each conjugated to cross-reactive material 197 (CRM197), and recombinant clumping factor A (ClfA).
Safety, tolerability, and immunogenicity were evaluated.
Results: At day 29 post-vaccination, robust immune responses were observed in both age cohorts at all three SA3Ag dose levels.
In the primary analysis population, the 50- to 85-year age stratum, geometric mean-fold-rises in competitive Luminex® immunoassay antibody titers from baseline ranged from 29.2 to 83.7 (CP5), 14.1 to 31.0 (CP8), and 37.1 to 42.9 (ClfA), all exceeding the pre-defined two-fold rise criteria.
Similar rises in opsonophagocytic activity assay titers demonstrated functionality of the immune response.
Most injection-site reactions were mild in severity and there were no substantial differences (SA3Ag vs. placebo) with regard to systemic or adverse events.
Conclusions: In this study of healthy adults aged 50-85 and 18-24 years, SA3Ag elicited a rapid and robust immune response and was well tolerated, with no notable safety concerns.