Serum Hemagglutination Inhibition Antibody (HI) Titer ≥40 Among Healthcare Personnel at 2010–2011 Preseason, Post–Trivalent Inactivated Vaccine, and End-of-Season by Influenza Vaccination History and by Preseason HI Titer
| No. of HCP With preseason, post-TIV and End-of-Season serum by Influenza Vaccination History . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer <40 . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer ≥40 . | No. of HCP With HI Titer ≥40 at Preseason, Post-TIV, or End-of-Season/All HCP . | Adjusteda Odds Ratio of HCP With HI Titer ≥40 (95% CI) . | Adjustedb Relative Risk of HCP With HI Titer ≥40 (95% CI) . |
|---|---|---|---|---|---|
| No./No. (%) . | No./No. (%) . | No./No. (%) . | |||
| Time 1 (preseason serum) (n = 1417) | |||||
| Yes MIIV and No TIV (n = 598) | NA | NA | 205/598 (34%)c | 5.24 (3.82–7.18) | 3.26 (2.72–3.81) |
| No MIIV and No TIV (n = 819) | NA | NA | 117/819 (14%) | 1.00 | 1.00 |
| Time 2 (post-TIV serum) (n = 865) | |||||
| Yes MIIV and Yes TIV (n = 489) | 171/335 (51%) | 150/154 (97%) | 321/489 (66%) | 0.66 (.45–.98) | 0.93 (.84–.997) |
| No MIIV and Yes TIV (n = 376) | 266/322 (83%) | 53/54 (98%) | 319/376 (85%) | 1.00 | 1.00 |
| Time 3 (end-of-season serum) (n = 1254) | |||||
| No MIIV and No TIV (n = 304) | 1/263 (0%) | 35/41 (85%) | 36/304 (12%) | 1.00 | 1.00 |
| No MIIV and Yes TIV (n = 405) | 219/350 (63%) | 54/55 (98%) | 273/405 (67%)d | 16.24 (10.34–25.52) | 5.79 (4.91–6.54) |
| Yes MIIV and No TIV (n = 56) | 0/26 (0%) | 29/30 (97%) | 29/56 (52%) | 10.87 (5.52–21.43) | 5.01 (3.60–6.27) |
| Yes MIIV and Yes TIV (n = 489) | 49/334 (15%) | 147/155 (95%) | 196/489 (40%)d | 8.33 (5.19–13.38) | 4.46 (3.47–5.43) |
| No. of HCP With preseason, post-TIV and End-of-Season serum by Influenza Vaccination History . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer <40 . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer ≥40 . | No. of HCP With HI Titer ≥40 at Preseason, Post-TIV, or End-of-Season/All HCP . | Adjusteda Odds Ratio of HCP With HI Titer ≥40 (95% CI) . | Adjustedb Relative Risk of HCP With HI Titer ≥40 (95% CI) . |
|---|---|---|---|---|---|
| No./No. (%) . | No./No. (%) . | No./No. (%) . | |||
| Time 1 (preseason serum) (n = 1417) | |||||
| Yes MIIV and No TIV (n = 598) | NA | NA | 205/598 (34%)c | 5.24 (3.82–7.18) | 3.26 (2.72–3.81) |
| No MIIV and No TIV (n = 819) | NA | NA | 117/819 (14%) | 1.00 | 1.00 |
| Time 2 (post-TIV serum) (n = 865) | |||||
| Yes MIIV and Yes TIV (n = 489) | 171/335 (51%) | 150/154 (97%) | 321/489 (66%) | 0.66 (.45–.98) | 0.93 (.84–.997) |
| No MIIV and Yes TIV (n = 376) | 266/322 (83%) | 53/54 (98%) | 319/376 (85%) | 1.00 | 1.00 |
| Time 3 (end-of-season serum) (n = 1254) | |||||
| No MIIV and No TIV (n = 304) | 1/263 (0%) | 35/41 (85%) | 36/304 (12%) | 1.00 | 1.00 |
| No MIIV and Yes TIV (n = 405) | 219/350 (63%) | 54/55 (98%) | 273/405 (67%)d | 16.24 (10.34–25.52) | 5.79 (4.91–6.54) |
| Yes MIIV and No TIV (n = 56) | 0/26 (0%) | 29/30 (97%) | 29/56 (52%) | 10.87 (5.52–21.43) | 5.01 (3.60–6.27) |
| Yes MIIV and Yes TIV (n = 489) | 49/334 (15%) | 147/155 (95%) | 196/489 (40%)d | 8.33 (5.19–13.38) | 4.46 (3.47–5.43) |
Abbreviations: CI, confidence interval; HCP, healthcare personnel; HI, hemagglutination inhibition antibody; MIIV, 2009–2010 A(H1N1) pandemic monovalent inactivated influenza vaccine; NA, not applicable; TIV, 2010–2011 trivalent inactivated influenza vaccine containing 2009 A (H1N1) pandemic component.
a Adjusted odds ratios (AORs) with 95% CIs are from multivariable logistic regression models adjusted for all descriptive characteristics listed in Table 1, including age and excluding age group and geometric mean titer and ordinal level of preseason A(H1N1)pdm09 HI titers. Statistically significant AORs (P < .05) are bolded. The covariates that were most influential in changing the AORs were age and site at preseason, post-TIV, and end-of-season and receipt of 2009–2010 seasonal influenza vaccine at preseason. Multiple other covariates changed AORs at end-of-season.
b Using the conversion formula proposed by Zhang et al [37], validated by Poisson regression with robust covariance.
c Bolded: Statistically significant difference in proportions with P < .05 by the χ2 test.
d HCP who received both 2009 MIIV and 2010–2011 TIV were significantly less likely to have HI ≥ 40 than those who received TIV only (AOR, 0.51 [95% CI, .38–.70]); adjusted relative risk, 0.76 [95% CI, .65–.88]).
Serum Hemagglutination Inhibition Antibody (HI) Titer ≥40 Among Healthcare Personnel at 2010–2011 Preseason, Post–Trivalent Inactivated Vaccine, and End-of-Season by Influenza Vaccination History and by Preseason HI Titer
| No. of HCP With preseason, post-TIV and End-of-Season serum by Influenza Vaccination History . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer <40 . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer ≥40 . | No. of HCP With HI Titer ≥40 at Preseason, Post-TIV, or End-of-Season/All HCP . | Adjusteda Odds Ratio of HCP With HI Titer ≥40 (95% CI) . | Adjustedb Relative Risk of HCP With HI Titer ≥40 (95% CI) . |
|---|---|---|---|---|---|
| No./No. (%) . | No./No. (%) . | No./No. (%) . | |||
| Time 1 (preseason serum) (n = 1417) | |||||
| Yes MIIV and No TIV (n = 598) | NA | NA | 205/598 (34%)c | 5.24 (3.82–7.18) | 3.26 (2.72–3.81) |
| No MIIV and No TIV (n = 819) | NA | NA | 117/819 (14%) | 1.00 | 1.00 |
| Time 2 (post-TIV serum) (n = 865) | |||||
| Yes MIIV and Yes TIV (n = 489) | 171/335 (51%) | 150/154 (97%) | 321/489 (66%) | 0.66 (.45–.98) | 0.93 (.84–.997) |
| No MIIV and Yes TIV (n = 376) | 266/322 (83%) | 53/54 (98%) | 319/376 (85%) | 1.00 | 1.00 |
| Time 3 (end-of-season serum) (n = 1254) | |||||
| No MIIV and No TIV (n = 304) | 1/263 (0%) | 35/41 (85%) | 36/304 (12%) | 1.00 | 1.00 |
| No MIIV and Yes TIV (n = 405) | 219/350 (63%) | 54/55 (98%) | 273/405 (67%)d | 16.24 (10.34–25.52) | 5.79 (4.91–6.54) |
| Yes MIIV and No TIV (n = 56) | 0/26 (0%) | 29/30 (97%) | 29/56 (52%) | 10.87 (5.52–21.43) | 5.01 (3.60–6.27) |
| Yes MIIV and Yes TIV (n = 489) | 49/334 (15%) | 147/155 (95%) | 196/489 (40%)d | 8.33 (5.19–13.38) | 4.46 (3.47–5.43) |
| No. of HCP With preseason, post-TIV and End-of-Season serum by Influenza Vaccination History . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer <40 . | No. of HCP With HI Titer ≥40 at Post-TIV, or End-of-Season/No. of HCP With Preseason HI Titer ≥40 . | No. of HCP With HI Titer ≥40 at Preseason, Post-TIV, or End-of-Season/All HCP . | Adjusteda Odds Ratio of HCP With HI Titer ≥40 (95% CI) . | Adjustedb Relative Risk of HCP With HI Titer ≥40 (95% CI) . |
|---|---|---|---|---|---|
| No./No. (%) . | No./No. (%) . | No./No. (%) . | |||
| Time 1 (preseason serum) (n = 1417) | |||||
| Yes MIIV and No TIV (n = 598) | NA | NA | 205/598 (34%)c | 5.24 (3.82–7.18) | 3.26 (2.72–3.81) |
| No MIIV and No TIV (n = 819) | NA | NA | 117/819 (14%) | 1.00 | 1.00 |
| Time 2 (post-TIV serum) (n = 865) | |||||
| Yes MIIV and Yes TIV (n = 489) | 171/335 (51%) | 150/154 (97%) | 321/489 (66%) | 0.66 (.45–.98) | 0.93 (.84–.997) |
| No MIIV and Yes TIV (n = 376) | 266/322 (83%) | 53/54 (98%) | 319/376 (85%) | 1.00 | 1.00 |
| Time 3 (end-of-season serum) (n = 1254) | |||||
| No MIIV and No TIV (n = 304) | 1/263 (0%) | 35/41 (85%) | 36/304 (12%) | 1.00 | 1.00 |
| No MIIV and Yes TIV (n = 405) | 219/350 (63%) | 54/55 (98%) | 273/405 (67%)d | 16.24 (10.34–25.52) | 5.79 (4.91–6.54) |
| Yes MIIV and No TIV (n = 56) | 0/26 (0%) | 29/30 (97%) | 29/56 (52%) | 10.87 (5.52–21.43) | 5.01 (3.60–6.27) |
| Yes MIIV and Yes TIV (n = 489) | 49/334 (15%) | 147/155 (95%) | 196/489 (40%)d | 8.33 (5.19–13.38) | 4.46 (3.47–5.43) |
Abbreviations: CI, confidence interval; HCP, healthcare personnel; HI, hemagglutination inhibition antibody; MIIV, 2009–2010 A(H1N1) pandemic monovalent inactivated influenza vaccine; NA, not applicable; TIV, 2010–2011 trivalent inactivated influenza vaccine containing 2009 A (H1N1) pandemic component.
a Adjusted odds ratios (AORs) with 95% CIs are from multivariable logistic regression models adjusted for all descriptive characteristics listed in Table 1, including age and excluding age group and geometric mean titer and ordinal level of preseason A(H1N1)pdm09 HI titers. Statistically significant AORs (P < .05) are bolded. The covariates that were most influential in changing the AORs were age and site at preseason, post-TIV, and end-of-season and receipt of 2009–2010 seasonal influenza vaccine at preseason. Multiple other covariates changed AORs at end-of-season.
b Using the conversion formula proposed by Zhang et al [37], validated by Poisson regression with robust covariance.
c Bolded: Statistically significant difference in proportions with P < .05 by the χ2 test.
d HCP who received both 2009 MIIV and 2010–2011 TIV were significantly less likely to have HI ≥ 40 than those who received TIV only (AOR, 0.51 [95% CI, .38–.70]); adjusted relative risk, 0.76 [95% CI, .65–.88]).
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