Sutter 1997.
| Methods |
Study design: placebo‐controlled (for both IPV and OPV), randomised trial Setting: Sohar Hospital, North Batinah, Oman Study dates: not reported |
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| Participants |
Sample size: 547 Dropouts/withdrawals: not reported Age: mean = 32.6 weeks at 7‐month OPV vaccination Sex: not reported Inclusion criteria: infants born at the Sohar regional hospital in North Batinah were randomised at birth Exclusion criteria: not reported |
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| Interventions |
Group 1 (n = 185): OOOO (O1) OO at birth, 1.5, 2.5 and 3.5 weeks, and 6, 7, and 9 months Group 2 (n = 172): O (O + I) (O + I) (O + I) (O1) OO at birth, 1.5, 2.5 , and 3.5 weeks, and 6, 7 and 9 months Group 3 (n = 190): III (O1) OO at birth, 1.5, 2.5, and 3.5 weeks, and 6, 7, and 9 months Placebo for IPV was diphtheria‐tetanus toxoid‐pertussis vaccine; placebo for OPV was molar magnesium chloride. IPV was manufactured by Pasteur‐Merieux Serums et Vaccins (Lyon, France) and formulated to contain 40, 8, and 32 D antigen units of poliovirus types 1, 2, and 3, respectively, and was combined with DTP per 0.5 mL dose. OPV was manufactured by SmithKline Beecham Biologicals (Rixensart, Belgium) |
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| Outcomes |
Timing of outcome assessment: 6 and 10 months. Follow‐up: 10 months |
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| Notes | ||
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "...were randomized at birth" |
| Allocation concealment (selection bias) | Unclear risk | Comment: not described |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | Comment: no blinding but performance is not likely to be influenced by lack of blinding in terms of intervention or co‐interventions |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Comment: probably blinded. Additionally, the objective outcome (antibody titres) is not likely to be influenced by lack of blinding. |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Comment: not reported |
| Selective reporting (reporting bias) | Low risk | Comment: no evidence of selecting reporting |
| Other bias | Low risk | Comment: no evidence of other bias |
| Conflict of interest | Low risk | Comment: financial support received from Global Programme for Vaccines and Immunization, WHO, Geneva, using funds donated by the governments of Finland and Sweden, the Rockefeller Foundation, and the United Nations Development Programme |