A Novel Unadjuvanted Subunit Respiratory Syncytial Virus Prefusion F Vaccine Induces Potent and Differentiated Functional Immune Responses Compared to AS01-Adjuvanted Arexvy in Older Adults

Licensed recombinant protein respiratory syncytial virus (RSV) vaccines can prevent substantial morbidity in older adults. However, revaccination to prevent waning protection may be suboptimal, prompting the exploration of candidates for heterologous boosting. In this clinical trial of RSV vaccine-naive older adults, we evaluated SCB-1019T, a novel unadjuvanted bivalent RSV prefusion F (preF) protein vaccine stabilized via Trimer-Tag technology, in comparison to the licensed AS01E-adjuvanted RSV vaccine Arexvy.

Citation:
Richmond P, Kwan TTL, Rook C, et al. A Novel Unadjuvanted Subunit Respiratory Syncytial Virus Prefusion F Vaccine Induces Potent and Differentiated Functional Immune Responses Compared to AS01-Adjuvanted Arexvy in Older Adults. Open Forum Infect Dis. 2026;13(1).

Keywords:
Respiratory Syncitial Virus; older adults; pre-fusion antigen; vaccine

Abstract:
Licensed recombinant protein respiratory syncytial virus (RSV) vaccines can prevent substantial morbidity in older adults. However, revaccination to prevent waning protection may be suboptimal, prompting the exploration of candidates for heterologous boosting. In this clinical trial of RSV vaccine-naive older adults, we evaluated SCB-1019T, a novel unadjuvanted bivalent RSV prefusion F (preF) protein vaccine stabilized via Trimer-Tag technology, in comparison to the licensed AS01E-adjuvanted RSV vaccine Arexvy.