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Table 2 Main outcomes of randomized trials of pneumococcal vaccines

From: Are the pneumococcal polysaccharide vaccines effective? Meta-analysis of the prospective trials

Outcome

Patient group

Number of trials

Number of patients

Percent affected without vaccine

Percent affected with vaccine

Relative risk (95%CI)

Number-needed-to-treat (95%CI)

All pneumonias

Healthy immunocompetent

3

14 567

6.5

3.1

0.56 (0.47 to 0.66)

29 (24 to 36)

 

Elderly or high risk

5

7 837

6.8

7

1.08 (0.92 to 1.27)

 

Pneumococcal pneumonias

Healthy immunocompetent

3

14 567

3.1

0.5

0.16 (0.11 to 0.23)

38 (33 to 45)

 

Elderly or high risk

7

22 479

1.9

1.7

0.88 (0.72 to 1.07)

 

Lower respiratory tract infection

Healthy immunocompetent

2

10 067

5.6

4.1

0.85 (0.71 to 1.02)

 
 

Elderly or high risk

3

17 195

9.4

9.9

1.06 (0.97 to 1.16)

 

Pneumonia-related death

Healthy immunocompetent

1

11 958

1.6

1.1

0.70 (0.50 to 0.96)

213 (114 to 1660)

 

Elderly or high risk

8

22 559

1.1

1

0.93 (0.72 to 1.20)

 

Pneumococcal bacteraemia

Healthy immunocompetent

1

5 427

3.8

0.7

0.18 (0.09 to 0.34)

32 (26 to 44)

 

Elderly or high risk

3

927

1.4

0.8

0.53 (0.14 to 1.94)

 
  1. Note: Details of patient groups are given in the textNumbers-needed-to-treat are only given where there is a statistical benefit of treatment over control.