Editorial Expression of Concern: Intranasal vaccination of hamsters with a Newcastle disease virus vector expressing the S1 subunit protects animals against SARS-CoV-2 disease(Scientific Reports, 10.1038/s41598-022-13560-z)

The Editors are issuing an Expression of Concern following an alert concerning potential undeclared Competing Interests in the Article. Following discussion with the Authors, the Editors also identified discrepancies between the published study and original ethical approval. The Authors provided information that a change in protocol was approved by their institution; however, it proved impossible to definitively confirm or refute that statement. Additionally, this Article appears to contain errors in Fig. 6, wherein subpanels rLS1-S1-F 5DPI and 10DPI show overlapping histological images, and rLS1-S1-F 2DPI and mock show overlapping histological images. These were incorrectly included as representative of different conditions. Images corresponding to the correct experimental conditions were provided by the Authors and the updated Figure appears below. Some of the files provided appeared to contain a labelling error. The readers are asked to interpret the Article with caution. Manolo Fernández Díaz, Katherine Calderón, Aldo Rojas-Neyra, Vikram N. Vakharia, Ricardo Choque- Guevara, Angela Montalvan-Avalos, Dora Rios-Matos, Luis Tataje-Lavanda, Yacory Sernaque-Aguilar, Doris Villanueva-Pérez, Ricardo Montesinos-Millán, Yudith Cauna-Orocollo, Katherine Vallejos-Sánchez, Dennis Núñez-Fernández, Luis A. Guevara-Sarmiento and Mirko Zimic agree to this Expression of Concern.