Table 2.
Pre- and Post-Vaccination Hemagglutination Inhibition Antibody Geometric Mean Titer and Mean Fold-Rise in Titer in the Second Year of the Randomized Immunogenicity Trial According to Quadrivalent Vaccine Combination Received in 2 Study Seasons, With Quadrivalent Inactivated Influenza Vaccine/Quadrivalent Inactivated Influenza Vaccine as Referent Group
| Hemagglutination Inhibition Antibody | IIV/IIV (Ref) | ccIIV/ccIIV | ccIIV/RIV | RIV/ccIIV | RIV/RIV | |||||
|---|---|---|---|---|---|---|---|---|---|---|
| n = 60 | n = 101 | n = 106 | n = 73 | n = 74 | ||||||
| GMT (99.3% CI)a or Mean Fold-Rise in Titer (99.3% CI)b | ||||||||||
| A/Idaho/07/2018 (H1N1) (cell-propagated A/Brisbane/02/2018-like) | ||||||||||
| ȃPre-vaccine GMT | 27.3 | (17.3–43.2) | 25.4 | (18.7–34.6) | 24.0 | (17.3–33.4) | 35.0 | (22.6–54.3) | 37.5 | (25.4–55.3) |
| ȃPost-vaccine GMT | 38.2 | (23.9–60.9) | 53.0 | (40.5–69.3) | 68.4 | (50.2–93.2) | 75.6 | (52.2–109.3) | 76.3 | (51.9–112.2) |
| ȃMean fold-rise | 1.4 | (1.1–1.7) | 2.1 | (1.7–2.6) | 2.8 | (2.2–3.6) | 2.2 | (1.7–2.8) | 2.0 | (1.6–2.5) |
| A/Kansas/14/2017 (H3N2) | ||||||||||
| ȃPre-vaccine GMT | 102.0 | (72.1–144.3) | 70.6 | (51.3–97.2) | 77.9 | (56.2–108.0) | 132.3 | (95.1–184.1) | 136.4 | (102.8–181.1) |
| ȃPost-vaccine GMT | 216.1 | (165.0–283.0) | 163.4 | (127.1–209.9) | 248.0 | (190.3–323.1) | 181.0 | (129.3–253.4) | 302.5 | (247.2–370.2) |
| ȃMean-fold rise | 2.1 | (1.6–2.9) | 2.3 | (1.7–3.1) | 3.2 | (2.4–4.3) | 1.4 | (1.1–1.8) | 2.2 | (1.6–3.0) |
| B/Colorado/06/2017 (Victoria) | ||||||||||
| ȃPre-vaccine GMT | 34.4 | (26.3–45.0) | 39.7 | (30.2–52.3) | 41.6 | (32.5–53.3) | 47.0 | (32.3–68.5) | 54.0 | (40.9–71.2) |
| ȃPost-vaccine GMT | 44.4 | (34.1–57.8) | 55.6 | (43.1–71.8) | 83.2 | (65.8–105.1) | 66.2 | (45.7–95.8) | 87.0 | (64.1–118.1) |
| ȃMean-fold rise | 1.3 | (1.1–1.5) | 1.4 | (1.1–1.7) | 2.0 | (1.6–2.4) | 1.4 | (1.1–1.7) | 1.6 | (1.3–1.9) |
| B/Phuket/3073/2013 (Yamagata) | ||||||||||
| ȃPre-vaccine GMT | 46.5 | (33.3–64.8) | 47.8 | (36.7–62.3) | 49.0 | (37.1–64.7) | 58.5 | (40.6–84.3) | 65.7 | (47.7–90.5) |
| ȃPost-vaccine GMT | 59.2 | (42.2–83.2) | 73.7 | (57.7–94.1) | 102.6 | (79.3–132.6) | 82.3 | (56.9–119.0) | 108.0 | (81.2–143.5) |
| ȃMean-fold rise | 1.3 | (1.0–1.6) | 1.5 | (1.3–1.8) | 2.1 | (1.7–2.6) | 1.4 | (1.1–1.7) | 1.6 | (1.3–2.0) |
Data shown for participants in per-protocol analysis according to 2-year vaccine combination actually received. Post-vaccination antibody titers were obtained approximately 28 days after year 2 vaccination.
Abbreviations: ccIIV, cell culture–based inactivated influenza vaccine (Flucelvax Quadrivalent, Seqirus); CI, confidence interval; GMT, geometric mean titer; IIV, quadrivalent inactivated influenza vaccine (Fluzone Quadrivalent, Sanofi Pasteur); RIV, recombinant IIV (Flublok, Sanofi Pasteur).
GMTs and 99.3% CIs were calculated using the t distribution applied to log-transformed titers.
Mean fold-rise and 99.3% CIs were defined as the geometric mean of the ratio of post-vaccination titer and pre-vaccination titer for each participant.