Comparative immunogenicity of enhanced seasonal influenza vaccines in older adults: a systematic review and meta-analysis

Abstract

Background.A number of enhanced influenza vaccines have been developed for use in older adults, including high-dose, MF59-adjuvanted, and intradermal vaccines.Methods. We conducted a systematic review examining the improvements in antibody responses measured by the hemagglutination inhibition assay associated with these enhanced vaccines, compared with each other and with the standard-dose (SD) vaccine using random effects models.Results. Thirty-nine trials were included. Compared with adults aged ≥60 years receiving SD vaccines, those receiving enhanced vaccines had significantly higher postvaccination titers (for all vaccine strains) and higher proportions with elevated titers ≥40 (for most vaccine strains). High-dose vaccine elicited 82% higher postvaccination titer to A(H3N2) compared with SD vaccine; this was significantly higher than the 52% estimated for MF59-adjuvanted versus SD vaccines (P = .04), which was higher than the 32% estimated for intradermal versus SD vaccines (P < .01).Conclusions. Overall, by summarizing current evidence, we found that enhanced vaccines had greater antibody responses than the SD vaccine. Indications of differences among enhanced vaccines highlight the fact that further research is needed to compare new vaccine options, especially during seasons with mismatched circulating strains and for immune outcomes other than hemagglutination inhibition titers as well as vaccine efficacy.

Safety, tolerability, and immunogenicity of influenza vaccination with a high-density microarray patch: Results from a randomized, controlled phase I clinical trial

“…Influenza causes significant morbidity and mortality in adults over 65 years of age, and strategies to improve vaccine coverage, immunogenicity, and effectiveness in this age group are required [48]. Currently IIVs for this population require chemical adjuvants such as MF59 or high doses of antigen (such as 60 μg HA per strain per dose present in HD Fluzone) to achieve satisfactory immune responses [48,49]. The enhanced immunogenicity seen with MAP delivery indicates that HD-MAPs may provide an alternative approach; however, whether any differences seen in the immune responses induced by HD-MAPs compared with IM injection are clinically relevant will require large-scale studies with clinical endpoints.…”

Influenza in temperate and tropical Asia: a review of epidemiology and vaccinology

“…53 Further, despite significantly higher HI titers 21-28 days after vaccination with these new vaccines compared to the standard dose inactivated vaccine, evidence of improved year-round antibody persistence is lacking (Table 2). 54 Access to these vaccines is also extremely limited, with none currently routinely available in an Asian country. 55…”

Evaluating the Relative Vaccine Effectiveness of Adjuvanted Trivalent Influenza Vaccine Compared to High-Dose Trivalent and Other Egg-Based Influenza Vaccines among Older Adults in the US during the 2017–2018 Influenza Season

“…In the US, there are two influenza vaccines that are currently approved specifically for the ≥65 population: adjuvanted trivalent influenza vaccine (aTIV; Fluad ® , Seqirus) and high-dose trivalent influenza vaccine (TIV-HD; Fluzone High-Dose ® , Sanofi Pasteur) [ 4 ]. These enhanced influenza vaccines present opportunities to reduce the influenza-related burden among older adults compared to standard influenza vaccines [ 3 , 5 ]. aTIV combines MF59 adjuvant (an oil-in-water emulsion of squalene oil) and a standard dose of antigen, and is designed to produce stronger, broader, and longer immune responses against the selected influenza vaccine strains [ 3 , 6 ].…”