Table 2.
Pooled crude and adjusted seasonal vaccine effectiveness against laboratory‐confirmed influenza by influenza type/subtype and A(H1N1)pdm09 genetic group 6B.1, overall, by age groups, by previous vaccination status and for the target group for vaccination. I‐MOVE/I‐MOVE+ multicentre case‐control study, influenza season 2015/16 (week 41/2015‐week 19/2016)
| Type/subtype | Analysis scenario | Na | Cases; vacc/Controls; vacca | Crude VEa , b | CI | Adjusted VEc | CI | ||
|---|---|---|---|---|---|---|---|---|---|
| A(H1N1)pdm09d | By age | All ages | 7358 | 2176;148/5182;527 | 41.9 | 28.9‐52.6 | 32.9 | 15.5‐46.7 | |
| 0‐14 y | 2424 | 648;14/1776;56 | 25.4 | −39.1 to 60.0 | 31.9 | −32.3 to 65.0 | |||
| 15‐64 y | 4308 | 1394;73/2914;230 | 40.8 | 21.1‐55.6 | 41.4 | 20.5‐56.7 | |||
| 65+ y | 625 | 134;61/491;240 | 26.8 | −14.4 to 53.1 | 13.2e | −38.0 to 45.3 | |||
| Target group for vaccination | All ages | 1953 | 520;114/1433;425 | 44.3 | 27.4‐57.2 | 33.0 | 10.8‐49.7 | ||
| 0‐14 y | 253 | 70;6/183;24 | 48.7 | −46.7 to 82.1 | 55.5f | −35.1 to 85.3 | |||
| 15‐64 y | 1061 | 315;47/746;155 | 45.2 | 18.9‐62.9 | 42.9 | 14.5‐61.9 | |||
| By vaccine type—all ages | Unvaccinated (ref) | 6683 | 2028/4655 | ||||||
| Subunit vaccine | 242 | 57/185 | 39.3 | 16.2‐56.1 | 33.9 | 6.7‐53.1 | |||
| Split virion vaccine | 255 | 62/193 | 47.6 | 28.6‐61.5 | 36.3 | 10.8‐54.5 | |||
| By vaccine type—0‐ to 14‐y‐olds | Unvaccinated (ref) | 2354 | 634/1720 | Ref | |||||
| Subunit vaccine | 24 | 4/20 | 46.2 | −68.5 to 82.8 | 51.1 | −55.8 to 84.6 | |||
| Split virion vaccine | 28 | 6/22 | 7.6 | −144.8 to 65.1 | 16.3 | −137.2 to 70.4 | |||
| By vaccine type—15‐ to 64‐y‐olds | Unvaccinated (ref) | 4005 | 1321/2684 | Ref | |||||
| Subunit vaccine | 112 | 27/85 | 43.5 | 9.9‐64.6 | 45.6 | 12.1‐66.4 | |||
| Split virion vaccine | 106 | 28/78 | 45.7 | 14.2‐65.6 | 45.2 | 11.8‐65.9 | |||
| By prior (2014/15) influenza vaccination status—≥9‐y‐olds | Neither | 4378 | 1404/2974 | Ref | Ref | ||||
| 2015/16 season only | 100 | 17/83 | 59.2 | 28.8‐76.6 | 54.7 | 19.6‐74.5 | |||
| 2014/15 season only | 146 | 38/108 | 19.0 | −20.3 to 45.5 | 8.0 | −39.3 to 39.2 | |||
| Study and previous season | 497 | 114/383 | 43.0 | 28.0‐54.9 | 28.4 | 6.2‐45.4 | |||
| By prior (2014/15) influenza vaccination status—≥9‐y‐olds, target group | Neither | 1106 | 335/771 | ||||||
| 2015/16 season only | 67 | 10/57 | 66.5 | 30.8‐83.8 | 60.4 | 16.0‐81.3 | |||
| 2014/15 season only | 85 | 14/71 | 53.6 | 12.8‐75.3 | 46.4 | −2.4 to 72.0 | |||
| Study and previous season | 428 | 95/333 | 46.4 | 28.0‐60.1 | 31.8 | 5.7‐50.7 | |||
| By prior (2014/15) influenza vaccination status—15‐ to 64‐y‐olds | Neither | 3707 | 1244/2483 | ||||||
| 2015/16 season only | 66 | 10/56 | 70.3 | 39.5‐85.4 | 68.2 | 34.4‐84.6 | |||
| 2014/15 season only | 102 | 30/72 | 11.0 | −40.1 to 43.4 | 12.7 | −38.9 to 45.1 | |||
| Study and previous season | 220 | 58/162 | 32.4 | 6.5‐51.2 | 32.1 | 4.2‐51.8 | |||
| A(H1N1)pdm09 clade 6B.1 | All ages | 4779 | 645;46/4134;434 | 45.5 | 18.4‐63.5 | 32.8 | −4.1 to 56.7 | ||
| 0‐14 y | 1505 | 191;5/1314;43 | 38.6 | −74.8 to 78.4 | 51.3 | −33.5 to 82.3 | |||
| 15‐64 y | 2840 | 417;19/2423;197 | 42.5 | −8.2 to 69.4 | 40.1 | −12.9 to 68.3 | |||
| 65+ y (sample size too small) | 406 | 36;22/370;189 | |||||||
| Influenza Bf | By age | 0‐14 y | 3304 | 1545;82/1759;52 | −81.4 | −159.2 to 26.9 | −47.6 | −124.9 to 3.1 | |
| 15‐64 y | 3606 | 1138;49/2468;196 | 46.4 | 25.4‐61.5 | 27.3 | −4.6 to 49.4 | |||
| 65+ y | 488 | 104;46/384;186 | 9.3 | −44.1 to 42.9 | |||||
| Target group for vaccination | 0‐14 y | 326 | 141;34/185;27 | −21.3 | −121.0 to 33.4 | 1.7g | −94.5 to 50.3 | ||
| 15‐64 y | 751 | 163;22/588;121 | 46.8 | 11.4‐68.1 | 38.4 | −6.6 to 64.4 | |||
| By vaccine type | 0‐ to 14‐y‐olds | Unvaccinated (ref) | 3170 | 1463/1707 | |||||
| Subunit vaccine | 50 | 31/19 | ‐93.7 | −246.0 to 8.4 | −56.4 | −202.1 to 19.0 | |||
| Split virion vaccine | 67 | 44/23 | −106.9 | −245.0 to 24.1 | −83.5 | −232.9 to 1.1 | |||
| 15‐ to 64‐y‐olds | Unvaccinated (ref) | 3361 | 1089/2272 | ||||||
| Subunit vaccine | 89 | 17/72 | 47.1 | 8.4‐69.4 | 17.7 | −48.0 to 54.3 | |||
| Split virion vaccine | 84 | 15/69 | 57.9 | 25.2‐76.3 | 44.4 | −2.8 to 70.0 | |||
| By prior (2014/15) influenza vaccination status | 15‐ to 64‐y‐olds | Neither | 3194 | 1055/2139 | |||||
| 2015/16 season only | 59 | 13/46 | 37.8 | −17.1 to 67.0 | 28.3 | −40.2 to 63.3 | |||
| 2014/15 season only | 77 | 16/61 | 49.1 | 10.0‐71.2 | 41.3 | −8.7 to 68.3 | |||
| Both seasons | 176 | 35/141 | 49.0 | 24.8‐65.4 | 23.7 | −16.8 to 50.2 | |||
Based on the complete case analysis, records with missing age, sex, chronic condition, vaccination status are dropped.
Crude VE adjusted by study site.
Data adjusted for age (restricted cubic spline or age group), onset date (restricted cubic spline), sex, chronic condition and study site unless otherwise indicated.
Study sites included in A(H1N1)pdm09 all ages and ≥9 y analysis: DE, ES, FR, HR, HU, IE, IT, NL, PL, PT, RO, SE; HU and HR not included in A(H1N1)pdm09 0‐14 y analysis; HR not included in A(H1N1)pdm09 15‐64 y analysis; study sites included in A(H1N1)pdm09 clade 6B.1 analysis of all ages and 15‐ to 64‐y‐olds: DE, ES, FR, HU, IE, NL, PT, RO, SE; HU not included in A(H1N1)pdm09 clade 6B.1 0‐14 y analysis; study sites included in B 0‐14 y analysis: DE, ES, FR, IE, IT, NL, PL, PT, SE; study sites included in B 15‐64 y analysis: DE, ES, FR, HU, IE, IT, NL, PL, PT, SE; study sites included in B 65 y and older analysis: DE, ES, FR, HR, HU, IE, IT, NL, PL, SE.
Adjusted by age and study site only.
Due to heterogeneity of VE estimates against influenza B between age groups, no “all ages” estimate against influenza B was attempted.
Adjusted by time and study site only.