TABLE 4.
Microneutralization antibody titers to A(H3N2) viruses following 2014-2015 IIV vaccination (n = 48) stratified by age and prior season vaccine typea
| Influenza virus strain and age group | 2013-2014 vaccination | No. of subjects | Geometric mean titer (95% CI) |
% subjects with the following postvaccine MN titer: |
Fold rise | % Seroconversion | ||
|---|---|---|---|---|---|---|---|---|
| Prevaccine | Postvaccine | ≥40 | ≥110 | |||||
| A/Texas/50/2012 (3C.1) | ||||||||
| 3- to 8-yr-old | IIV | 18 | 124 (51–300) | 855 (434–1,686) | 94 | 94 | 6.9 | 61 |
| 9- to 17-yr-old | IIV | 25 | 269 (175–413) | 478 (354–646) | 100 | 100 | 1.8 | 20 |
| LAIV | 5 | 150 (53–426) | 926 (353–2,430) | 100 | 100 | 6.2 | 100 | |
| A/Nebraska/04/2014 (3C.2a) | ||||||||
| 3- to 8-yr-old | IIV | 18 | 20 (11–36) | 115 (63–212) | 89 | 72 | 5.8 | 50 |
| 9- to 17-yr-old | IIV | 25 | 20 (13–30) | 40 (27–60) | 56 | 20 | 2.0 | 8 |
| LAIV | 5 | 25 (11–57) | 176 (81–379) | 100 | 80 | 7.1 | 80 | |
| A/Switzerland/9715293/2013 (3C.3a) | ||||||||
| 3- to 8-yr-old | IIV | 18 | 17 (9–30) | 105 (52–211) | 83 | 72 | 6.2 | 50 |
| 9- to 17-yr-old | IIV | 25 | 24 (15–41) | 51 (33–79) | 68 | 32 | 2.1 | 20 |
| LAIV | 5 | 13 (6–28) | 124 (26–599) | 80 | 60 | 9.4 | 80 | |
a
Note that five study participants who were not vaccinated in the 2013–2014 season were excluded from this analysis.