CLEVELAND – Influenza vaccine response is affected both by preexisting immunity to influenza and older age, according to a new study, which pointed out that frailty, an indicator of functional impairment in older adults, also has been shown to be a factor in one study of non-veterans.
An article in the journal Clinical and Vaccine Immunology reported on a study to determine the association between frailty, preexisting immunity and immune response to influenza vaccine in older veterans.1
For the investigation, researchers led by Louis Stoke Cleveland VAMC researchers analyzed 117 subjects – median age 81 — divided into three 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.
Post-vaccination samples were obtained after participants received the seasonal trivalent inactivated influenza vaccine and compared to baseline. Anti-influenza humoral immunity as measured by hemagglutinin inhibition (HI) and microneutralization (MN) assays were used to identify influenza B, A(H1N1)pdm09 and A(H3N2) viruses.
Results indicated that post vaccination-titers to Influenza vaccine were not different between frail and non-frail subjects overall in this older subset of veterans. Preexisting HI titers strongly correlated with post-vaccination titers among all functional status groups, however.
“When microneutralization titers are compared, the association between preexisting immunity and vaccine response varies by frailty status with the highest correlation observed in the [non-frail] subjects,” study authors wrote. “In conclusion, preexisting immunity rather than frailty appear to predict post-influenza vaccine titer in this older veteran cohort.”
- Van Epps P, Tumpey T, Pearce MB, Golding H, Higgins P, Hornick T, Burant C, Wilson BM, Banks R, Gravenstein S, Canaday DH. Preexisting Immunity Not Frailty Phenotype Predicts Influenza Post Vaccination Titers Among Older Veterans. Clin Vaccine Immunol. 2017 Jan 18. pii: CVI.00498-16. doi: 10.1128/CVI.00498-16. [Epub ahead of print] PubMed PMID: 28100496.