Abstract: We included eight RCTs of 1562 children receiving oral homeopathic medicinal products or a control treatment (placebo or conventional treatment) for upper respiratory tract infections (URTIs). Four treatment studies examined the effect on URTI recovery, and four studies investigated the effect on preventing URTIs after one to three months of treatment, followed up for the remainder of the year. Two treatment and two prevention studies involved homeopaths individualising treatment. The other studies used predetermined, non-individualised treatments. All studies involved highly diluted homeopathic medicinal products. We found several limitations to the included studies, in particular methodological inconsistencies and high attrition rates, failure to conduct intention-to-treat analysis, selective reporting, and apparent protocol deviations. We assessed three studies as at high risk of bias in at least one domain, and many had additional domains with unclear risk of bias. Three studies received funding from homeopathy manufacturers; one support from a non-government organisation; two government support; one was cosponsored by a university; and one did not report funding support. Methodological inconsistencies and significant clinical and statistical heterogeneity precluded robust quantitative meta-analysis. Only four outcomes were common to more than one study and could be combined for analysis. Odds ratios (OR) were generally small with wide confidence intervals (CI), and the contributing studies found conflicting effects, so there was little certainty that the efficacy of the intervention could be ascertained. All studies assessed as at low risk of bias showed no benefit from oral homeopathic medicinal products; trials at uncertain and high risk of bias reported beneficial effects. We found low-quality evidence that non-individualised homeopathic medicinal products confer little preventive effect on ARTIs (OR 1.14, 95% CI 0.83 to 1.57). We found low-quality evidence from two individualised prevention studies that homeopathy has little impact on the need for antibiotic usage (N = 369) (OR 0.79, 95% CI 0.35 to 1.76). We also assessed adverse events, hospitalisation rates and length of stay, days off school (or work for parents), and quality of life, but were not able to pool data from any of these secondary outcomes. There is insufficient evidence from two pooled individualised treatment studies (N = 155) to determine the effect of homeopathy on short-term cure (OR 1.31 favouring placebo, 95% CI 0.09 to 19.54; very low-quality evidence) and long-term cure rates (OR 0.99, 95% CI 0.10 to 9.67; very low-quality evidence). Adverse events were reported inconsistently; however, serious events were not reported. One study found an increase in the occurrence of non-severe adverse events in the treatment group. Pooling of two prevention and two treatment studies did not show any benefit of homeopathic medicinal products compared to placebo on ARTI recurrence or cure rates in children. We found no evidence to support the efficacy of homeopathic medicinal products for ARTIs in children. Adverse events were poorly reported, so conclusions about safety could not be drawn.

Plain-language summary: We included eight studies involving 1562 children that compared oral homeopathic treatment to either placebo or standard treatment to prevent or treat respiratory infections in children. All studies investigated upper respiratory tract (from the nose to the windpipe (trachea)) infections, but one combined reporting of upper and lower respiratory tract (from the windpipe to the lungs and pleura (membranes covering the lungs)) infections, so the numbers of children with upper or lower infections is unknown. Three studies received funding from homeopathy manufacturers; one reported support from a non-government organisation; two received government support; one was cosponsored by a university; and one did not report funding support. Studies investigated a range of interventions for various illnesses and populations using different outcome measures, so only a small number could be combined for analysis. All moderate-quality studies (low risk of bias) showed little or no beneficial effects for homeopathic medicinal products, whether individualised by a trained homeopath or a standard, non-individualised commercially available therapy. Where results could be combined, there was probably little or no difference in benefit on short- or long-term cure, or in prevention of ARTI. Two low-quality studies (unclear or high risk of bias) showed some benefit of homeopathic medicinal products for a limited number of outcomes. One study showed a reduction in disease severity for the homeopathy group at some time points. The other study showed a reduction in number of respiratory infections over the following year in the treatment groups, although more than a quarter of participants were not accounted for in the results. There was no difference between homeopathy and placebo groups for parents' time off work, antibiotic use, or adverse effects. Consequently, there is no convincing evidence homeopathic medicinal products are effective in treating ARTIs in children. We are unsure about safety because data on adverse events were poorly reported. We rated evidence as moderate or low quality for most outcomes. Three outcomes provided very low-quality evidence because study populations and results differed significantly among studies; there were significant limitations in study design and reporting; and sample sizes were small.