Rate of serious adverse eventsNo major side effects of preventive antibiotic therapy were reported. *The absolute risk is calculated using the absolute numbers of events in both study arms. CI: confidence interval; RR: risk ratio; UTIs: urinary tract infections. GRADE Working Group grades of evidence. High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.a Large number of included studies, large number of participants, and small confidence interval (ultimately low risk of bias). Good applicability in clinical practice. b Limited publication bias cannot be excluded, as funnel plots for primary outcomes were skewed at the base, towards good outcomes.c Regarding risk of bias of individual included studies, more than two of the included studies scored at least one criterion of 'unclear' and/or 'high' risk of bias on the Cochrane 'Risk of bias' summary (Figure 1). However, the e ect on primary outcomes was consistent among studies with 'low' risk of bias.d Regarding consistency of e ect, heterogeneity was substantial (I = 79%). However, overall e ect estimates were precise. Stratifying for included studies with 'low risk of bias' resulted in loss of heterogeneity (I = 4%) and did not a ect outcomes. Therefore, we did not downgrade the quality of evidence. e Downgraded owing to multiple remarks on GRADE considerations, despite the fact that all remarks can be explained and rectified.f Regarding consistency of e ect, heterogeneity was moderate (I = 56%). However, overall e ect estimates were precise. Therefore, we did not downgrade the quality of evidence.