Table 3. Geometric mean titers for 2011–2012 influenza A vaccine and selected historical strains, overall and stratified by age.
| Vaccine Strain | Geometric Mean Titers Mean (95% CI) |
*P value | ||
|---|---|---|---|---|
| Overall (n = 264) |
Age 50–64 y (n = 157) |
Age 65–80 y (n = 107) |
||
| A(H1N1) | ||||
| A/California/07/2009 Day 0 | 23.7 (21.1–26.7) | 26.2 (22.1–31.0) | 20.5 (17.6–23.9) | 0.038 |
| A/California/07/2009 Day 21 | 50.9 (44.5–58.2) | 55.0 (45.8–65.9) | 45.5 (37.5–55.4) | 0.177 |
| A/Puerto Rico/8/1934 | 21.9 (19.5–24.5) | 16.8 (14.8–19.2) | 32.1 (26.7–38.6) | <0.001 |
| A/Fort Monmouth/1/1947 | 31.9 (28.4–35.9) | 27.0 (23.2–31.4) | 40.8 (34.1–48.7) | <0.001 |
| A/Texas/36/1991 | 40.3 (35.2–46.2) | 42.7 (35.7–51.1) | 37.0 (29.9–45.8) | 0.312 |
| A/New Caledonia/20/1999 | 62.2 (54.7–70.7) | 59.0 (49.7–70.1) | 67.2 (55.4–81.4) | 0.332 |
| A/Solomon Islands/3/2006 | 27.8 (24.5–31.5) | 32.4 (27.2–38.6) | 22.2 (18.8–26.1) | 0.004 |
| A/Brisbane/59/2007 | 11.8 (11.3–12.4) | 12.4 (11.5–13.3) | 11.1 (10.4–11.8) | 0.039 |
| A(H3N2) | ||||
| A/Perth/16/2009 Day 0 | 19.9 (17.8–22.3) | 21.5 (18.4–25.1) | 17.9 (15.4–20.9) | 0.105 |
| A/Perth/16/2009 Day 21 | 46.0 (40.2–52.5) | 49.0 (41.2–58.3) | 41.9 (34.0–51.5) | 0.256 |
| A/Sydney/5/1997 | 55.8 (48.5–64.3) | 51.4 (42.7–62.0) | 63.0 (51.0–78.0) | 0.165 |
| A/Panama/2007/1999 | 87.7 (77.2–99.6) | 84.0 (71.1–99.2) | 93.5 (76.6–114.0) | 0.420 |
| A/Fujian/411/2002 | 105.8 (92.8–120.6) | 98.4 (82.7–117.2) | 117.7 (96.5–143.4) | 0.192 |
| A/Wisconsin/67/2005 | 46.0 (40.1–52.7) | 44.5 (36.9–53.6) | 48.3 (39.8–58.6) | 0.562 |
| A/Brisbane/10/2007 | 41.5 (36.2–47.6) | 42.4 (35.3–50.8) | 40.3 (32.8–49.4) | 0.720 |
GMT, geometric mean titer. *P value comparing the 2 age groups obtained by ANOVA for log-transformed titers.