Table 2 Overall and sensitivity analysis results of immunogenicity of intradermal versus intramuscular administration of influenza vaccine

All studies

6

673

1.00 (0.91-1.1)

0.272;21.5

6

673

1.00 (0.9-1.12)

0.042;56.6

6

673

0.99 (0.84-1.16)

0.072;50.5

High quality^b

5

566

1.01 (0.86-1.18)

0.177; 36.7

5

566

1.02 (0.88-1.19)

0.05;57.9

5

566

0.98 (0.79-1.22)

0.041;59.8

Low quality^b

1

107

1.02 (0.94-1.11)

-

1

107

0.98 (0.92-1.05)

-

1

107

0.94 (0.79-1.16)

-

Antigen content ≥12 μg

3

358

1.13 (0.9-1.43)

0.248;28.4

3

358

1.03 (0.77-1.39)

0.01;78.4

3

358

0.94 (0.61-1.47)

0.01;78.1

Antigen content ≤ 9 μg

3

315

0.95 (0.8-1.14)

0.067;63

3

315

0.99 (0.93-1.05)

0.368;0.1

3

315

0.96 (0.84-1.09)

0.935;0

One injection

4

377

0.99 (0.86-1.15)

0.136;45.9

4

377

1.04 (0.9-1.2)

0.087;54. 3

4

377

0.98 (0.87-1.11)

0.783;0

Two injections

2

296

1.05 (0.84-1.3)

0.291;10.2

2

296

0.96 (0.72-1.29)

0.015;83.1

2

296

0.8 (0.34-1.99)

0.003;88.8

Mantoux technique

2

263

0.93 (0.71-1.24)

0.012;84

2

263

1.00 (0.89-1.13)

0.177;45.2

2

263

0.95 (0.82-1.1)

0.819;0

Micro injection system

4

410

1.06 (0.92-1.22)

0.378;2.9

4

410

1.02 (0.83-1.26)

0.027;67.4

4

410

0.98 (0.73-1.32)

0.027;67.4

 Transplantation

4

344

1.11 (0.86-1.43)

0.228;30.7

4

344

1.04 (0.8-1.35)

0.22;68.9

4

344

0.91 (0.61-1.36)

0.018;70.2

 Other diseases^b

3

488

0.98 (0.87-1.1)

0.216;34.7

3

488

0.99 (0.93-1.05)

0.465;0

4

488

0.97 (0.86-1.1)

0.98;0

All studies

5

517

1.00 (0.84-1.19)

0.532;0

5

517

1.08 (0.86-1.36)

0.569;0

5

517

0.92 (0.72-1.17)

0.578;0

High quality^b

4

410

1.04 (0.79-1.36)

0.399; 0

4

410

1.00 (0.75-1.34)

0.52;0

4

410

1.13 (0.77-1.66)

0.823;0

Low quality^b

1

107

0.98 (0.78-1.23)

-

1

107

1.23 (0.83-1.83)

-

1

107

0.80 (0.59-1.09)

-

Antigen content ≥12 μg

3

358

1.17 (0.85-1.62)

0.545;0

3

358

1.06 (0.73-1.55)

0.36;2

3

358

1.11 (0.7-1.75)

0.641;0

Antigen content ≤ 9 μg

2

159

0.95 (0.77-1.16)

0.443;0

2

159

1.1 (0.81-1.45)

0.35;0

2

159

0.85 (0.64-1.13)

0.33;0

One injection

3

221

0.99 (0.74-1.34)

0.242;29.6

3

221

1.16 (0.86-1.57)

0.341;7

3

221

0.86 (0.65-1.13)

0.589;0

Two injections

2

296

1.09 (0.77-1.55)

0.961;0

2

296

0.94 (0.63-1.4)

0.735;0

2

296

1.14 (0.68-1.9)

0.359;0

Mantoux technique

1

107

0.98 (0.78-1.23)

-

1

107

1.23 (0.83-1.83)

-

1

107

0.80 (0.59-1.09)

-

Micro injection system

4

410

1.04 (0.79-1.36)

0.399; 0

4

410

1.00 (0.75-1.34)

0.52;0

4

410

1.13 (0.77-1.66)

0.823;0

Cause of immunosuppression:

 Transplantation

3

358

1.17 (0.85-1.62)

0.545;0

3

358

1.06 (0.73-1.55)

0.36;2

3

358

1.11 (0.7-1.75)

0.641;0

 Other diseases^c

2

159

0.95 (0.77-1.16)

0.443;0

2

159

1.1 (0.81-1.45)

0.35;0

2

159

0.85 (0.64-1.13)

0.33;0