Abstract: We identified five RCTs that randomised 544 children (three studies) and 205 adults (exclusively from two studies). They all compared saline irrigation to routine care or other nose sprays, rather than placebo. We included two new trials in this update, which did not contribute data of sufficient size or quality to materially change the original findings. Most trials were small and we judged them to be of low quality, contributing to an unclear risk of bias. Most outcome measures differed greatly between included studies and therefore could not be pooled. Most results showed no difference between nasal saline treatment and control. However, one larger trial, conducted with children, did show a significant reduction in nasal secretion score (mean difference (MD) -0.31, 95% confidence interval (CI) -0.48 to -0.14) and nasal breathing (obstruction) score (MD -0.33, 95% CI -0.47 to -0.19) in the saline group. However, a MD of -0.33 on a four-point symptom scale may have minimal clinical significance. The trial also showed a significant reduction in the use of decongestant medication by the saline group. Minor nasal discomfort and/or irritation was the only side effect reported by a minority of participants. Nasal saline irrigation possibly has benefits for relieving the symptoms of acute URTIs. However, the included trials were generally too small and had a high risk of bias, reducing confidence in the evidence supporting this. Future trials should involve larger numbers of participants and report standardised and clinically meaningful outcome measures.

Plain-language summary: We identified five studies, with a total of 749 participants enrolled and 565 participants providing data, which addressed the research question and met the inclusion criteria. They all compared saline irrigation with routine care or other nose sprays. These studies covered a wide range of ages, countries, sample sizes, dosing methods and frequency, and time since onset of URTI symptoms. They were also highly variable in their design and the symptoms that were measured. This is not surprising due to the lack of consistent measures of URTI symptoms and signs. This resulted in very few common outcome measures that could be combined across these five studies. The evidence is current to August 2014. The two additional studies included since the original systematic review have not contributed data of sufficient size or quality to materially change the original findings. Only the largest study, which studied 401 children aged 6 to 10 years, found significant reductions in a number of symptoms, including nasal secretions, sore throat, nasal breathing score and nasal obstruction, as well as reduced use of additional nasal decongestant medications. It also reported a significant improvement in the health status score. There was a reduction in the outcome of time to resolution of symptoms, which was reported in two trials on adult participants, but the difference was not clinically significant. Nasal saline is safe but may cause minor adverse effects, such as irritation or a burning sensation, particularly with products using higher flows or concentrations. Most studies were small and had significant shortcomings in the design or implementation of the research. Further studies, preferably larger in size and using common outcome measures, are needed to establish the potential for the role of nasal saline irrigation in reducing the severity and duration of acute URTI symptoms, secondary infections and possibly antibiotic usage.