Quality assessment and summary of findings according to the GRADE approach.

aOR: adjusted odds ratio; aRR: adjusted risk ratio; HBV: hepatitis B virus; HCV: hepatitis C virus; HIV: human immunodeficiency virus; MSM: men who have sex with men; OR: odds ratio; RR: risk ratio; TTI: transfusion transmissible infections1 Inappropriate eligibility criteria (random donors are a mix of male and female, while all homosexuals included are male); control for confounding unclear (not mentioned in article); other limitations: homosexuals were solicited via the press, other donors were random samples)2 Random samples with young, minority and first-time donor oversampled; possible recall bias; the possible difference between respondents and non-respondents is not known3 Control for confounding unclear (not mentioned in the article); no control group was included (e. g. states where no change in deferral policy was implemented): several blood safety-related interventions were implemented during the 10-year period covered by this study; there is a potential decline in the number of HIV-positive donors presenting to donate because of earlier HIV diagnosis in more recent times; before the implementation of the new policy, different states/territories had different policies (permanent deferral or 5 year deferral since last MSM contact) and the implementation of the new policy was not established at the same moment in each state/territory.4 Control for confounding unclear (not mentioned in the article); no control group was included (e. g. states where no change in deferral policy was implemented)5 First-time donations by infected persons (53.3%) were 1.7-fold higher than those among the control group (31.1%), which suggests that test-seeking donations may have been numerous.6 Control for confounding unclear (not clear for which factors adjustment was made); questionnaire used to obtain information7 Methods for exposure and outcome variables unclear (risk factors not determined in the same way for all cases); not controlled for confounding ((not clear if individuals with MSM as risk factor also have other risk factors)8 Inappropriate eligibility criteria (all subjects had positive anti-HCV findings by enzyme immunoassay); not controlled for confounding9 Inappropriate eligibility criteria (cases and controls not matched); not controlled for confounding (individuals with MSM as risk factor also have other risk factors); 5 out of 7 cases having homosexual contact also admitted personal drug use; questionnaire used10 Control for confounding unclear (only adjusted for intravenous drug use, but unclear if this is sufficient)11 Control for confounding unclear (only adjusted for intravenous drug use, but unclear if this is sufficient); questionnaire used to obtain information12 Control for confounding unclear (only donors with no histories of transfusion or intravenous drug abuse, but unclear if this is sufficient); interview used to obtain information13 Inappropriate eligibility criteria (cases and controls not matched; all subjects positive by ELISA); unclear if cases and controls received same questionnaire; control for confounding unclear (donors do not have former intravenous drug addiction, but unclear if this is sufficient); questionnaire used to obtain information14 Inappropiate eligibility criteria (cases and controls not matched; all subjects positive by ELISA); not controlled for confounding (individuals with MSM as risk factor can also have other risk factors); interview used to obtain information15 Low number of events16 Calculations made by the reviewer(s) using Review Manager software17 Not able to calculate confidence interval (data lacking)18 Raw data calculated based on total number of participants and percentages19 Raw data not available20 Confidence interval of adjusted odds ratio not available, only p-valueQuality assessment and summary of findings according to the GRADE approach.