BACKGROUND Nosocomial infections continue to be a significant cause of morbidity and mortality among preterm and/or low birth weight (LBW) infants. Preterm infants are deficient in immunoglobulin G (IgG); therefore, administration of intravenous immunoglobulin (IVIG) may have the potential of preventing or altering the course of nosocomial infections. OBJECTIVES To use systematic review/meta-analytical techniques to determine whether IVIG administration (compared
with placebo or no intervention) to preterm (< 37 weeks' postmenstrual age (PMA) at birth) or LBW (< 2500 g birth weight) infants or both is effective/safe in preventing nosocomial infection. SEARCH METHODS For this update, MEDLINE, EMBASE, CINAHL, The Cochrane Library, Controlled Trials, ClinicalTrials.gov and PAS Abstracts2view were searched in May 2013. SELECTION CRITERIA We selected randomised controlled trials (RCTs) in which a group of participants to whom IVIG was given was compared with a control group that received a placebo or no intervention for preterm (< 37 weeks' gestational age) and/or LBW (< 2500 g) infants. Studies that were primarily designed to assess the effect of IVIG on humoral immune markers were excluded, as were studies in which the follow-up period was one week or less. DATA COLLECTION AND ANALYSIS Data collection and analysis was performed in accordance with the methods of the Cochrane Neonatal Review Group. MAIN RESULTS Nineteen studies enrolling approximately 5000 preterm and/or LBW infants met inclusion criteria. No new trials were identified in May 2013.When all studies were combined, a significant reduction in sepsis was noted (typical risk ratio (RR) 0.85, 95% confidence interval (CI) 0.74 to 0.98; typical risk difference (RD) -0.03, 95% CI 0.00 to -0.05; number needed to treat for an additional beneficial outcome (NNTB) 33, 95% CI 20 to infinity), and moderate between-study heterogeneity was reported (I(2) 54% for RR, 55% for RD). A significant reduction of one or more episodes was found for any serious infection when all studies were combined (typical RR 0.82, 95% CI 0.74 to 0.92; typical RD -0.04, 95% CI -0.02 to -0.06; NNTB 25, 95% CI 17 to 50), and moderate between-study heterogeneity was observed (I(2) 50% for RR, 62% for RD). No statistically significant differences in mortality from all causes were noted (typical RR 0.89, 95% CI 0.75 to 1.05; typical RD -0.01, 95% CI -0.03 to 0.01), and no heterogeneity for RR (I(2) = 21%) or low heterogeneity for RD was documented (I(2) = 28%). No statistically significant difference was seen in mortality from infection; in incidence of necrotizing enterocolitis (NEC), bronchopulmonary dysplasia (BPD) or intraventricular haemorrhage (IVH) or in length of hospital stay. No major adverse effects of IVIG were reported in any of these studies. AUTHORS' CONCLUSIONS IVIG administration results in a 3% reduction in sepsis and a 4% reduction in one or more episodes of any serious infection but is not associated with reductions in other clinically important outcomes, including mortality. Prophylactic use of IVIG is not associated with any short-term serious side effects.The decision to use prophylactic IVIG will depend on the costs and the values assigned to the clinical outcomes. There is no justification for conducting additional RCTs to test the efficacy of previously studied IVIG preparations in reducing nosocomial infections in preterm and/or LBW infants.