Table 5.
Proportion of subjects with ≥4-fold rise in antibody titers after vaccination with H2N2 LAIV or Placebo
| After 1 dose (Day 28) LAIV: N=27 placebo: N=9 | After 2 doses (Day 56) LAIV: N=27 placebo: N=7 | After 2 doses (Day 112) LAIV: N=25 placebo: N=7 | Cumulative conversions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Assay | Test article | n (%) | 95% CI | n (%) | 95% CI | n (%) | 95% CI | n (%) | 95% CI |
| HAI: serum Ab | LAIV | 5 (18.5) | 8.2–36.7 | 9 (33.3) | 18.6–52.2 | 15 (60.0)1 | 40.7–76.6 | 16 (59.3) | 40.7–75.5 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | 0 | 0.0–34.5 | 0 | 0.0–29.9 | |
| MN: serum Ab | LAIV | 8 (29.6) | 15.9–48.5 | 12 (44.4)2 | 27.6–62.7 | 12 (48.0) | 26.7–62.9 | 16 (59.3) | 40.7–75.5 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | 0 | 0.0–34.5 | 0 | 0.0–29.9 | |
| ELISA: serum IgA | LAIV | 2 (7.4) | 2.1–23.4 | 14 (51.9)3 | 34.0–69.3 | 12 (48.0)4 | 30.0–66.5 | 14 (51.9) | 34.0–69.3 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | 0 | 0.0–34.5 | 0 | 0.0–29.9 | |
| ELISA: serum IgG | LAIV | 0 | 0.0–12.5 | 1 (3.7) | 0.7–18.3 | 2 (8.0) | 2.2–25.0 | 2 (7.4) | 2.1–23.4 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | 0 | 0.0–34.5 | 0 | 0.0–29.9 | |
| ELISA: nasal IgA | LAIV | 6 (22.2) | 10.6–40.8 | 11 (40.7) | 24.5–59.3 | n/a | n/a | 13 (48.1) | 30.7–66.0 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | n/a | n/a | 0 | 0.0–29.9 | |
| ELISA: salivary IgA | LAIV | 3 (11.1) | 3.9–28.1 | 9 (33.3) | 18.6–52.2 | n/a | n/a | 12† (44.4) | 27.6–62.7 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | n/a | n/a | 0 | 0.0–29.9 | |
| Cumulative conversions | LAIV | 15 (55.6)5 | 37.3–72.4 | 23 (85.2)6 | 67.5–94.1 | 21 (84.0)7 | 65.3–93.6 | 23 (85.2) | 67.5–94.1 |
| Placebo | 0 | 0.0–29.9 | 0 | 0.0–34.5 | 0 | 0.0–34.5 | 0 | 0.0–29.9 | |
CI, 95% confidence interval as calculated by Wilson test; n/a – not applicable (nasal swab and saliva samples were not collected at Day 112); HAI – hemagglutination inhibition assay; MN – microneutralization; ELISA - Enzyme-linked immunosorbent assay; Ab – antibody;
†2 subjects had 4-fold rises in salivary IgA antibody titer at Day 56 compared to Day 28, and only 2-fold rise at Day 56 compared to Day 0;
1percent of subjects with HAI Ab conversions 84 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.008);
2percent of subjects with MN Ab conversions 28 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.036);
3percent of subjects with serum IgA conversions 28 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.026);
4percent of subjects with serum IgA conversions 84 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.029);
5cumulative percent of subjects with Ab conversions is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.005);
6cumulative percent of subjects with Ab conversions 28 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.0001);
7cumulative percent of subjects with Ab conversions 56 d after 2nd vaccination is significantly higher in LAIV group than in Placebo group (Fisher exact (2–tailed) p = 0.0001);