Sperber 1989.

Methods	Double‐blind, placebo‐controlled, experimental colds
Participants	40 inoculated, 31 colds, mean age 21 years, 39.1% women, setting not reported, fever ≤ 37.7 °C
Interventions	Ibuprofen 200 mg, 2 doses for the first day and 4 doses for the subsequent 4 days
Outcomes	4‐point scale. Moderate to marked severity (2‐ to 3‐point) was reduced in the ibuprofen group (18% versus 29%) but statistical significance was not reported
Notes	Adverse effects were slightly more frequent in the ibuprofen group (6/23) than in the control group (4/23)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"... were randomly assigned to receive" Comment: insufficient information about the sequence generation process
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information about the allocation concealment
Blinding (performance bias and detection bias) All outcomes	Low risk	"... two identically appearing capsules" Comment: probably done
Incomplete outcome data (attrition bias) All outcomes	Low risk	Among 58 inoculated participants, 8 were excluded (7 not infected, 1 infected with wild type virus), 1 was withdrawn
Selective reporting (reporting bias)	Unclear risk	No protocol, no convincing text
Other bias	Low risk	The study appears to be free of other sources of bias