Table 2.
Crude and adjusted influenza monovalent and trivalent vaccine effectiveness by camp and subtype, 31 May 2009 to 30 June 2012 (n = 7016)
| Subtype | Influenza vaccine effectiveness (%) [95% confidence interval (CI)] | |||||
|---|---|---|---|---|---|---|
| Subjects with ≤14 days vaccination being classified as vaccination group (n = 7016) | Subjects with ≤14 days vaccination being classified as no vaccination group (n = 7016) | |||||
| Crude | Adjusted* | Crude | Adjusted* | |||
| Recruit Camp | Other Camps | Recruit Camp | Other Camps | |||
| Monovalent Vaccine effectiveness | ||||||
| Influenza A(H1N1)pdm09, Period 2** | 72 (59–81) | 80 (70–87) | 65 (−48 to 92) | 94 (87–98) | 97 (92–99) | 63 (−57 to 91) |
| Trivalent Vaccine effectiveness | ||||||
| Influenza A(H1N1)pdm09, Period 3** | 71 (49–84) | 81 (64–90) | 5 (−222 to 72) | 69 (41–84) | 76 (49–88) | 30 (−162 to 81) |
| Influenza A(H1N1)pdm09, Period 4** | 83 (23–96) | 97 (49–100) | 44 (−208 to 90) | 46 (−144 to 88) | 89 (−66 to 99) | 24 (−331 to 87) |
| Influenza A(H3N2), Period 3** | 60 (7–83) | −115 (−1748 to 75) | 42 (−80 to 82) | 59 (−5 to 84) | 1 (−391 to 80) | 56 (−56 to 88) |
| Influenza A(H3N2), Period 4** | 49 (−55 to 83) | 80 (16–95) | −73 (−127 to 78) | 24 (−91 to 70) | 71 (−23 to 93) | 3 (−357 to 79) |
| Influenza B, Period 3** | 86 (69–93) | 90 (77–96) | 69 (−163 to 96) | 88 (66–96) | 91 (71–97) | 65 (−192 to 96) |
| Influenza B, Period 4** | 70 (45–83) | 71 (45–85) | 65 (−39 to 91) | 92 (84–96) | 95 (88–98) | 72 (−1·8 to 92) |
| Overall Influenza***, Period 3** | 77 (65–84) | 83 (73–90) | 39 (−34 to 72) | 76 (61–85) | 81 (66–89) | 52 (−13 to 79) |
| Overall Influenza***, Period 4** | 69 (49–81) | 77 (59–87) | 34 (−83 to 76) | 83 (73–89) | 93 (86–97) | 47 (−31 to 79) |
*
Variables being adjusted in all logistic regression models are camp group, vaccination period, vaccination history and interaction between vaccination history and camp group.
**
Period 1 refers to the pre-vaccination period; period 2 refers to the period new recruits were given monovalent vaccination; period 3 refers to the period new recruits were given trivalent vaccination; and period 4 refers to the period all SAF servicemen received trivalent vaccination.
***
The overall influenza includes influenza A(H1N1)pdm09, influenza A(H3N2) and influenza B.