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Table 2 Quality assessment of vaccine trials for immunization against – Shigella

From: Vaccines for the prevention of diarrhea due to cholera, shigella, ETEC and rotavirus

  Quality Assessment Summary of Findings
     Directness No of events  
No of Studies Design Limitations Consistency Generalizability to population of interest Generalizability to intervention of interest Intervention Control Risk Ratio
Efficacy against morbidity, Shigella Infection (S.Flexneri): Low-outcome-specific quality
03 [35, 38, 40] RCT Random effect model. Insignificant results Two studies show consistent benefit Two studies were from developed countries Two used oral vaccine while one used intramuscular 56 107 0.72 (0.37, 1.39)b
02 [35, 38] RCT Random effect model. Insignificant results One study shows significant benefit One study from developed country Oral Vaccines 49 99 0.67 [0.28, 1.59]b
01 [40] RCT Only one study   Study was conducted in Israel Parenteral Vaccine 07 08 0.92 [0.33, 2.53]
Efficacy against morbidity, Shigella Infection (S.Sonnei): Low-outcome-specific quality
03 [35, 38, 40] RCT Random effect model. Insignificant results Two studies show consistent benefit Two studies were from developed countries Two used oral vaccine while one used intramuscular 39 94 0.47 (0.12, 1.85)b
02 [35, 38] RCT Random effect model. Insignificant results One study shows significant benefit One study from developed country Oral Vaccines 10 56 0.39 [0.04, 4.33]b
01 [40] RCT Only one study   Study was conducted in Israel Parenteral Vaccines 29 38 0.73 [0.45, 1.17]
One or more Adverse events (S.Flexneri): Low outcome-specific quality
02 [36, 41] RCT None inconsistent results Both from developing countries   45 08 1.58(0.81, 3.07)a
  1. a: Fixed Effect Model
  2. b: Random Effect Model