We thank Gibb et al. for their Letter to the Editor ‘Revisiting the Efficacy of Bismuth Subsalicylate for the Prevention of Traveler’s Diarrhea’1 that was written to provide additional context regarding our manuscript ‘Efficacy of Bismuth Subsalicylate on the Prevention of Travelers’ Diarrhea, 2018–2023’.2 In their Letter, the authors offer a few explanations about why the clinical trial failed to detect a protective effect of bismuth subsalicylate (BSS) for travellers’ diarrhoea (TD). We agree with Gibb et al. that if participants had longer trip durations this may have resulted in increased rates of TD and an evident protective effect. However, we disagree with assumptions made about the pre-COVID and post-COVID results. The clinical trial did not reach statistical power and the number of participants reporting TD in each group were small (pre-COVID: 17 BSS vs 8 placebo; post COVID: 10 BSS vs 18 placebo); therefore, any observed TD incidence trends are not necessarily a true difference. Also, these observed differences may be influenced by various confounding factors (e.g. differences in travel destinations, reporting inconsistencies).
Funding
The work of the clinical trial in which this correspondence is in reference to was supposed by Procter & Gamble, CDC, and The New York Center for Travel and Tropical Medicine through a Cooperative Research and Development Agreement (D-129–18-00). Procter & Gamble provided the study medication and placebo but did not participate in the study procedures (i.e. data collection or analysis) to minimize the potential for any commercial influences or the appearance thereof.
Footnotes
Conflict of interest
The authors have no known financial interests with Procter & Gamble, the authors of the Letter to the Editor in which this correspondence is in response to. CDC has held a Cooperative Research and Development Agreement (CRADA) (D-129–18-00) with Procter & Gamble for projects on other topics; the CRADA was renewed for support of the initial clinical trial in reference.
Disclaimer
The findings and conclusions of this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control (CDC).
References
- 1.Gibb RD, Brum JM, Sloan KJ, Pitz AM, Circello BT, Grayling RA. Revisiting the efficacy of bismuth subsalicylate for the prevention of traveler’s diarrhea. J Travel Med 2025;taaf076. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Angelo KM, Salah Z, Rogova M et al. Efficacy of bismuth subsalicylate on the prevention of travelers’ diarrhea, 2018–2023. J Travel Med 2025;taaf047. [DOI] [PMC free article] [PubMed] [Google Scholar]