In older individuals, respiratory syncytial virus (RSV) infections cause considerable morbidity and hospitalization. In this study, researchers looked at the humoral, mucosal, and B cell responses to MEDI7510, an experimental adjuvanted RSV sF vaccine. They collected blood and nasal secretions at days 0, 8, 29, 91, and 180 post-vaccination to measure F-specific IgG and IgA antibodies by ELISA, and plasmablasts and memory B cells by IgA/G dual-color fluorospot in a substudy of a randomized, double-blind, placebo-controlled study of MEDI7510 in adults 60 years of age. The 27 vaccination recipients and 18 placebo receivers were 73 years old on average, with 24 women among them. On Day 8 post-immunization, 93 percent of vaccines had significant increases in F-specific plasma IgG; 85 percent had increased plasma IgA; 74 percent had increased nasal IgG and 26 percent nasal IgA; 93 percent had IgG and 89 percent IgA plasmablasts; and 82 percent had IgG and 7.4 percent IgA memory B cell responses to the vaccine.
In older people, this adjuvanted vaccination elicited strong humoral immune responses, including RSV F-specific systemic and mucosal antibodies and memory B cells. Nonetheless, being over 70 years old was related with a reduction in the immunogenicity of the adjuvanted vaccination.