1. Risk of bias criteria.

Random sequence generation	Was the allocation sequence adequately generated, for example with random number tables or computer‐generated random numbers? We assessed trials as being at low risk of bias (the method used is either adequate or unlikely to introduce confounding), uncertain risk of bias (there is insufficient information to assess whether the method used is likely to introduce confounding) or high risk of bias (the method used (e.g. quasi‐randomised trials) is improper and likely to introduce confounding).
Allocation concealment	Was allocation adequately concealed in a way that would not allow either the investigators or the participants to know or influence allocation to an intervention group before an eligible participant was entered into the study (for example using central randomisation or sequentially numbered, opaque, sealed envelopes held by a third party)? We judged trials to be at low risk of bias (the method used (e.g. central allocation) is unlikely to induce bias in the final observed effect), uncertain risk of bias (there is insufficient information to assess whether the method used is likely to induce bias in the estimate of effect) or high risk of bias (the method used (e.g. open random allocation schedule) is likely to induce bias in the final observed effect).
Masking (blinding)	We judged the possibility of masking being done on both participants and outcome assessors. We did not consider masking of personnel as this is not feasible in these trials. Were the participants and study outcome assessors masked from knowledge of which intervention a participant received? We judged trials to be at low risk of bias (the outcome measurement is not likely to be influenced by lack of masking), uncertain risk of bias (there is insufficient information to assess whether the type of masking used is likely to induce bias in the estimate of effect) or high risk of bias (the outcome or the outcome measurement is likely to be influenced by lack of masking).
Incomplete outcome data	Were incomplete outcome data adequately addressed? Incomplete outcome data essentially include: attrition, exclusions and missing data. If any withdrawals occurred, were they described and reported by treatment group with reasons given? We recorded whether or not there were clear explanations for withdrawals and dropouts in the treatment groups. An example of an adequate method to address incomplete outcome data is the use of an intention to‐treat analysis (ITT). We judged trials to be at low risk of bias (the underlying reasons for missing data are unlikely to make treatment effects depart from plausible values, or proper methods have been employed to handle missing data), uncertain risk of bias (there is insufficient information to assess whether the missing data mechanism in combination with the method used to handle missing data is likely to induce bias in the estimate of effect), or high risk of bias (the crude estimate of effects (e.g. complete case estimate) clearly was biased due to the underlying reasons for missing data, and the methods used to handle missing data are unsatisfactory).
Selective reporting	Are reports of the study free from any suggestion of selective outcome reporting? This was interpreted as no evidence that statistically non‐significant results might have been selectively withheld from publication, for example selective under‐reporting of data or selective reporting of a subset of data. We judged trials to be at low risk of bias (the trial protocol is available and all of the trials prespecified outcomes that are of interest in the review have been reported or similar), uncertain risk of bias (there is insufficient information to assess whether the magnitude and direction of the observed effect is related to selective outcome reporting), or high risk of bias (not all of the trials prespecified primary outcomes have been reported or similar).
Other sources of bias	Was trial funded from parties that might not have conflicting interests (e.g. an antibacterial agent manufacturer), or any academic, professional, financial or other benefits to the person responsible for the trial were independent of the direction or statistical significance of trial results? We assessed trials as being at low risk of bias (if trial funding did not come), unclear risk of bias (if the source of funding was not clear, or if it was unclear whether the person responsible for the trial stands to benefit according to the direction or statistical significance of trial results) or high risk of bias (if the trial’s source of funding had a conflict of interest, or if any academic, professional, financial or other benefits to the person responsible for the trial are dependent on the direction or statistical significance of trial results).