TABLE 3.
HAI and NAI antibody responses to influenza A and B in subjects with PCR-confirmed influenza in the immunology cohort
| Age (yrs) | Antibody titera | Influenza A |
Influenza B |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| n | HAI | 95% CI | P for age | NAI | 95% CI | P for age | By HAI or NAI | n | HAI | 95% CI | P for age | NAI | 95% CI | P for age | By HAI or NAI | ||
| 0–4 | GMT 1 | 6 | 86 | 12–609 | 36 | 5–247 | 1 | 10 | NA | 5 | NA | ||||||
| GMT 2 | 1220 | 401–3,714 | 160 | 36–709 | 10 | NA | 160 | NA | |||||||||
| GMFC | 14 | 3–73 | 5 | 1–20 | 0 | NA | 32 | NA | |||||||||
| %SC | 83 | 41–126 | 50 | –8–108 | 83 | 0 | NA | 100 | NA | 100 | |||||||
| 5–19 | GMT 1 | 4 | 320 | 184–557 | 0.1262b | 34 | 24–47 | 0.9960b | 1 | 20 | NA | 0.8833b | 2560 | NA | 0.0002b | ||
| GMT 2 | 226 | 153–335 | 0.0185c | 28 | 19–42 | 0.1067c | 10 | NA | 0.5437c | 2560 | NA | 0.0483c | |||||
| GMFC | 1 | 1 | 0.0014d | 1 | 1 | 0.0673d | 1 | NA | 0.4127d | 1 | NA | 0.1885d | |||||
| %SC | 0 | 0–0 | 0.0156e | 0 | 0–0 | 0.2082e | 0 | 0 | NA | 0.5760e | 0 | NA | 0.3368e | 0 | |||
| 20+ | GMT 1 | 59 | 59 | 40–88 | 34 | 25–46 | 23 | 11 | 7–18 | 1280 | 815–2,011 | ||||||
| GMT 2 | 144 | 91–227 | 55 | 39–77 | 32 | 18–58 | 3258 | 2063–5145 | |||||||||
| GMFC | 2 | 2–3 | 2 | 1–2 | 3 | 2–5 | 3 | 1–5 | |||||||||
| %SC | 34 | 22–46 | 25 | 14–37 | 44 | 39 | 18–61 | 35 | 14–56 | 48 | |||||||
a
GMT, geometric mean titer; GMFC, geometric mean fold change. The percent seroconversion (%SC) was determined as the percentage of individuals that seroconverted, as defined by a 4-fold rise in antibody titer by the specified assay between the first and second sera.
b
Age versus GMT 1 by ANOVA.
c
Age versus GMT 2 by ANOVA.
d
Age versus GMFC by ANOVA.
e
Age versus the percent seroconversion by ANOVA.