Kirke DN, et al. - In this case series and literature review, researchers ascertained if the presence of a concomitant upper respiratory tract infection (URI) affects the efficacy of Botulinum toxin (BoNT) in patients with spasmodic dysphonia (SD). From November 2016 to December 2017, all SD patients with a concurrent URI, presenting for BoNT therapy at a clinical research center were involved. In total, 12 patients [median age was 55 years (± 19.5)] have been identified. According to findings, some patients are reported to be affected while the interplay between disease and BoNT effectiveness is yet to be elucidated. They recommend that SD patients presenting with a concomitant URI for BoNT administration should be advised that the effect of their treatment may be reduced.