Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Sustained virological response
Systematic review	257 people defined as biochemically non-responsive at entry to the studies 2 RCTs in this analysis	Proportion of people with a sustained virological response 7/130 (5%) with 24 weeks retreatment with interferon 21/127 (17%) with 48 weeks retreatment with interferon	RR (for failure to achieve sustained virological response) 0.87 95% CI 0.79 to 0.96	Small effect size	longer retreatment with interferon