|Outcome||Effect||Number of participants|
|Certainty in the evidence*|
Assessed using a variety of scales
|Most studies showed small reductions in symptoms or no effect.||623|
(5 randomised trials)
(due to serious risk of bias and imprecision)
The outcome of interest is respiratory symptoms (for which a single pooled effect estimate was not available and only a narrative synthesis of the evidence was provided).
*Commonly used symbols to describe certainty in evidence in evidence profiles: high certainty ⊕⊕⊕⊕, moderate certainty ⊕⊕⊕O, low certainty ⊕⊕OO and very low certainty ⊕OOO.
†Serious risk of bias across studies because of unclear or inadequate blinding, sequence generation and allocation concealment.
‡Serious imprecision and inconsistency were considered together as there were small effects, or ‘no effects’ reported in studies (likely due to wide CIs).