Modlin 1997.
| Methods |
Study design: open‐label, randomised trial Setting: 3 Baltimore area paediatric practices, USA Study dates: 1991 to 1993 |
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| Participants |
Sample size: 510 infants Dropouts/withdrawals: 101* (42* due to relocation or change of physician, 34* due to noncompliance with study visits, 28* due to parental request) Age: Not reported Sex: male = 266, female = 244 Inclusion criteria: not reported Exclusion criteria: not reported |
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| Interventions |
Group A (n = 102): IIO at 2, 4, 15 months Group B (n = 105): IIOO at 2, 4, 6, 15 months Group C (n = 101): I (I + O) OO at 2, 4, 6, 15 months Group D (n = 99): III at 2, 4, 15 months Group E (n = 103): OOO at 2, 4, 15 months |
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| Outcomes |
Timing of outcome assessment: 2, 6, 15, 18 months |
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| Notes | *Exact figures taken from study report | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk |
Quote: "Infants were assigned by the Moses‐Oakford randomization algorithm" Quote: "There were no meaningful differences among the study groups in sex, race, mean age at each study visit, or withdrawal rate (data not shown)." |
| 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: no blinding but objective outcome (antibody titres) is not likely to be influenced by lack of blinding |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Quote: "Of the subjects, 101 (20%) withdrew from the study before the 18month visit." |
| 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 | Unclear risk | Comment: financially supported by Connaught Laboratories, Inc, Swiftwater, Pennsylvania (now Pasteur‐Merieux‐Connaught); National Immunization Program, Centers for Disease Control and Prevention, Atlanta |