Immunogenicity and safety of Intanza(®)/IDflu(®) intradermal influenza vaccine in South Korean adults: a multicenter, randomized trial

Abstract

Intanza(®)/IDflu(®) (Sanofi Pasteur, Lyon, France) is an intradermal inactivated trivalent influenza vaccine developed as an alternative to intramuscular influenza vaccine. The objective of this study was to confirm the immunogenicity and safety of Intanza/IDflu in South Korean adults. In a phase IV multicenter trial, South Korean adults 18-59 y old (n = 120) and ≥ 60 y old (n = 120) were randomized 1:1 to receive a single dose of Intanza/IDflu (9 µg for 18-59 y, 15 µg for ≥ 60 y) or trivalent intramuscular vaccine (Vaxigrip(®) 15 µg, Sanofi Pasteur, Lyon, France). Blood was collected on pre-vaccination (day 0) and on day 21. Hemagglutination inhibition titers, seroprotection rates and seroconversion rates were determined on day 21. Geometric mean titers, seroprotection and seroconversion rates were similar between the intradermal and intramuscular vaccines in both age groups for all three vaccine strains (A/H1N1, A/H3N2 and B). Both vaccines met Committee for Medicinal Products for Human Use criteria for all three strains. Solicited systemic reactions of the intradermal groups were generally mild, transient, and similar to those of the intramuscular groups. Solicited injection site reactions were more frequent in the intradermal groups but were mostly mild, transient, and consisted mainly of pain, erythema, and pruritus. No treatment-related serious adverse events or other safety concerns were reported. These results confirm that Intanza/IDflu is an effective and well-tolerated alternative to IM influenza vaccination. (Clinicaltrials.gov NCT ID: NCT01215669).

Keywords: Influenza vaccine; immunogenicity; intradermal; intramuscular; safety.

Figures

Figure 1. Prevaccination geometric mean titers and seroprotection rates. (A) Geometric mean titers (GMTs) for the 18−59 y age groups at day 0. (B) GMTs for the ≥ 60 y age groups at day 0. (C) Seroprotection rates for the 18−59 y age groups at day 0. (D) Seroprotection rates for the ≥ 60 y age groups at day 0. ID: intradermal vaccine; IM: intramuscular vaccine.

Figure 2. Immunogenicity outcomes after intradermal (ID) or intramuscular (IM) influenza vaccination in the 18−59 y age group. Subjects were vaccinated with 9 μg ID vaccine or with 15 μg IM vaccine, and immunogenicity characteristics were determined 21 d later. (A) Geometric mean titers (GMTs) at day 21. (B) GMT ratios (GMTRs), which were the geometric means of the day 21 hemagglutinin inhibition (HI) titer divided by the pre-vaccination (day 0) HI titer for each subject. (C) Seroprotection rates. Error bars indicate the 95% confidence intervals, and the horizontal bars indicate the Committee for Medicinal Products for Human Use criteria for adults 18–59 y old.

Figure 3. Immunogenicity outcomes after intradermal (ID) or intramuscular (IM) influenza vaccination in the ≥ 60 y age group. Subjects were vaccinated with 15 μg ID vaccine or with 15 μg IM vaccine, and immunogenicity characteristics were determined 21 d later. (A) Geometric mean titers (GMTs) at day 21. (B) GMT ratios (GMTRs), which were the geometric means of the day 21 hemagglutinin inhibition (HI) titer divided by the pre-vaccination (day 0) HI titer for each subject. (C) Seroprotection rates. (D) Seroconversion rates. Error bars indicate the 95% confidence intervals, and the horizontal bars indicate the Committee for Medicinal Products for Human Use criteria for adults ≥ 60 y old.

Figure 4. Solicited injection site and systemic reaction profiles. (A) Solicited injection site reactions. (B) Solicited systemic reactions. Data are the percentages of subjects within each group who experienced a grade 1 or 2 reaction or a grade 3 reaction through post-vaccination day 7. ID: intradermal vaccine; IM: intramuscular vaccine.