Dear Editor,

I have read with great interest the systematic review and meta-analysis on zinc supplementation and neonatal sepsis by Irfan et al. [1]. I would like to bring to your notice that the authors have included three studies that may have serious overlapping of included infants. I am referring to the three studies of Banupriya Newton et al. [2-4]. These studies have been conducted in the same center, with an important time overlap and even share the same registration codes (CTRI/2012/03/002517 and CTRI/2014/08/004866) [2-4]. Unfortunately, this is not the first time that these studies are wrongly combined in a meta-analysis on the topic [5]. Being a meta-analysis based on a very limited number of studies, this potential duplication may have seriously affected the validity of the results reported by Irfan et al. [1].

The authors have no conflicts of interest to declare.

None.

Eduardo Villamor conceived and wrote the letter.

This article is licensed under the Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC). Usage and distribution for commercial purposes requires written permission. Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug. Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.