Abstract: We included seven trials involving 486 infants and children aged up to three years. The immunoglobulin preparations used in these trials included anti-RSV immunoglobulin and the monoclonal antibody preparations palivizumab and motavizumab. We assessed the primary outcomes of mortality, length of hospital stay, and adverse events as providing low- or very low-certainty evidence due to risk of bias and imprecision. All trials were conducted at sites in high-income countries (USA, Chile, New Zealand, Australia), with two studies including a site in a middle-income country (Panama). Five of the seven studies were "supported" or "sponsored" by the trial drug manufacturers. We found no evidence of a difference between immunoglobulins and placebo for mortality (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.14 to 5.27; 3 trials; 196 children; 4 deaths; 2 deaths amongst 98 children receiving immunoglobulins, and 2 deaths amongst 98 children receiving placebo. One additional death occurred in a fourth trial, however, the study group of the child was not known and the data were not included in the analysis; very low-certainty evidence), and length of hospitalisation (mean difference −0.70, 95% CI −1.83 to 0.42; 5 trials; 324 children; low-certainty evidence). There was no evidence of a difference between immunoglobulins and placebo in adverse events of any severity or seriousness (reported in five trials) or serious adverse events (four trials) (RR for any severity 1.18, 95% CI 0.78 to 1.78; 340 children; low-certainty evidence, and for serious adverse events 1.08, 95% CI 0.65 to 1.79; 238 children; low-certainty evidence). We found no evidence of a significant difference between immunoglobulins and placebo for any of our secondary outcomes. We identified one ongoing trial. We found insufficient evidence of a difference between immunoglobulins and placebo for any review outcomes. We assessed the evidence for the effects of immunoglobulins when used as a treatment for RSV lower respiratory tract infection in hospitalised infants and young children as of low or very low certainty due to risk of bias and imprecision. We are uncertain of the effects of immunoglobulins on these outcomes, and the true effect may be substantially different from the effects reported in this review. All trials were conducted in high-income countries, and data from populations in which the rate of death from RSV infection is higher are lacking.

Plain-language summary: We included seven randomised controlled trials (studies in which participants are assigned to one of two or more treatment groups using a random method) that compared the effects of immunoglobulins with placebo in 486 young children hospitalised with RSV lung infections. All trials were conducted at sites in the USA; three trials included some children from South American countries (Chile and Panama); and one trial also included children from New Zealand and Australia. The trials were published between 1987 and 2014. Five trials were supported by the manufacturer of the immunoglobulin tested in the studies. One trial was supported by a government agency, and one trial did not describe how it was funded. Immunoglobulins did not appear to be more effective than placebo in preventing deaths among young children with RSV infection, although few deaths occurred in the trials. Immunoglobulins given to children hospitalised with RSV lung infection did not decrease the time spent in hospital. Children treated with immunoglobulins experienced adverse effects of any severity or seriousness and adverse effects considered to be serious (such as respiratory failure) as often as children treated with placebo. There was no difference between immunoglobulins and placebo for any other outcomes measured in the trials, such as the need for oxygen or admission to the intensive care unit. Data from populations in which the rate of death from RSV infection is higher are lacking. The quality of the evidence was low or very low, which means that the true effect of immunoglobulin treatment for young children in hospital with RSV lung infection may be very different from the findings of this review.