Notice of Retraction. Walach H, et al. Experimental Assessment of Carbon Dioxide Content in Inhaled Air With or Without Face Masks in Healthy Children: A Randomized Clinical Trial. JAMA Pediatr. Published online June 30, 2021.

The Research Letter, “Experimental Assessment of Carbon Dioxide Content in Inhaled Air With or Without Face Masks in Healthy Children: A Randomized Clinical Trial,” by Harald Walach, PhD, and colleagues published online in JAMA Pediatrics on June 30, 2021,¹ is hereby retracted. Following publication, numerous scientific issues were raised regarding the study methodology, including concerns about the applicability of the device used for assessment of carbon dioxide levels in this study setting, and whether the measurements obtained accurately represented carbon dioxide content in inhaled air, as well as issues related to the validity of the study conclusions. In their invited responses to these and other concerns, the authors did not provide sufficiently convincing evidence to resolve these issues, as determined by editorial evaluation and additional scientific review. Given fundamental concerns about the study methodology, uncertainty regarding the validity of the findings and conclusions, and the potential public health implications, the editors have retracted this Research Letter.

Corresponding Author: Phil B. Fontanarosa, MD, MBA, JAMA and JAMA Network, 330 N Wabash Ave, Chicago, IL 60611 (phil.fontanarosa@jamanetwork.org).

Published Online: July 16, 2021. doi:10.1001/jamapediatrics.2021.3252

Conflict of Interest Disclosures: None reported.