Scientific Publications by FDA Staff

Clin Vaccine Immunol 2017 Mar 6;24(3):e00498-16

Preexisting Immunity Not Frailty Phenotype Predicts Influenza Post Vaccination Titers Among Older Veterans.

Van Epps P, Tumpey T, Pearce MB, Golding H, Higgins P, Hornick T, Burant C, Wilson BM, Banks R, Gravenstein S, Canaday DH

Both preexisting immunity to influenza and age have been shown to be a correlate of influenza vaccine response. Frailty, an indicator of functional impairment in older adults, has also been shown in one study to predict lower influenza vaccine responses among non-veterans. In the current study we aimed to determine the association between frailty, preexisting immunity and immune response to influenza vaccine in older veterans. We analyzed 117 subjects (age range 62-95 years; median 81) divided into 3 cohorts based on the Fried frailty test: non-frail (NF: N=23; median age 68), pre-frail (PF: N=50; median age 80) and frail (F:N=44; median age 82) during the 2010-2011 and 11-12 influenza seasons. Subjects received the seasonal trivalent inactivated influenza vaccine and baseline and post-vaccination samples were obtained. Anti-influenza humoral immunity as measured by hemagglutinin inhibition (HI) and microneutralization (MN) assays were measured for influenza B, A(H1N1)pdm09 and A(H3N2) viruses. Post vaccination-titers to Influenza vaccine were not different between frail and NF subjects overall in this older subset of veterans. However, preexisting HI titers strongly correlated with post-vaccination titers among all functional status groups. When microneutralization titers are compared, the association between preexisting immunity and vaccine response varies by frailty status with the highest correlation observed in the NF subjects. In conclusion, preexisting immunity rather than frailty appear to predict post-influenza vaccine titer in this older veteran cohort.