Faden 1990.

Methods	Study design: open‐label, randomised trial Setting: children's hospital, Buffalo, USA Study dates: not reported
Participants	Sample size: 123 children naive to polio vaccination Dropouts/withdrawals: 35 Age: mean ages of children in each group ranged between 8.9 and 9.6 weeks at enrolment Sex: not reported Inclusion criteria: "Male and female infants 6‐10 weeks old were enrolled in the study from physicians' practices and the hospital's well child clinic. The children were free from apparent illness at the time of immunization." (quote) Exclusion criteria: "Children with major medical problems, in particular immune deficiency disorders, were excluded." (quote); "Patients were excluded from the efficacy analysis if they had fewer than three visits, were >13.5 weeks old at visit 1, were given the wrong vaccine, or had an unacceptable amount of time between visits[*]" (quote)
Interventions	Group A (n = 23): OOO at 2, 4 and 12 months Group B (n = 65): III at 2 4 and 12 months Group C (n = 17): IOO at 2, 4 and 12 months Group D (n = 18): IIO at 2, 4 and 12 months Oral vaccine (Orimune; Lederle, Wayne, NJ) prepared in monkey kidney cells contained antigen doses of: poliovirus type 1, 2, and 3. Inactivated vaccine (Imovax Polio; Merieux Institute, Lyon, France) prepared in Vero cells contained antigen doses of: poliovirus type 1.40 D antigen units (DAU); type 2, 8 DAU; and type 3.32 DAU.
Outcomes	Serum neutralising antibodies to polio virus 1, 2 and 3 Nasopharyngeal neutralising antibodies to polio virus 1, 2 and 3 Polio virus shedding Timing of outcome assessment: 2, 4, 5, 12, 13 and 60 months
Notes	*"The acceptable time between visits was visit 1 (2 months) to visit 2 (4 months), 6‐10 weeks; visit 2 to visit 3 (5 months), 3‐8 weeks; visit 3 to visit 4 (12 months), 6‐10 months; visit 4 to visit 5 (13 months), 3‐8 weeks. A patient excluded at one visit was excluded at all subsequent visits." (quote)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "Infants were randomized to one of four treatment groups" Quote: "Differences in mean age at visit 1 were not significant (P = .49, one‐way analysis of variance)."
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 the objective outcomes (antibody titres and poliovirus shedding) are not likely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) All outcomes	High risk	Comment: patients were excluded from the efficacy analysis if they had fewer than three visits, were > 13.5 weeks old at visit 1, were given the wrong vaccine, or had an unacceptable amount of time between visits. Of the 158 children enrolled in the study, 35 were excluded; thus, 123 were analysed and 86 of them were assessed for their long‐term immunity.
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: supported by grant from Merieux Institute, Miami, and National Institutes of Health (AI‐15939), and for long‐term immunity assessment, from Pasteur Merieux, Swiftwater, Pennsylvania