Reconsidering the inclusion of Ladapo's work in the meta-analysis: Validity concerns and implications.

This is a response to Marchand & Masoud's response letter regarding my criticism "Response to Dr. Somovilla del Saz's letter to the editor regarding "Risk of all-cause and cardiac-related mortality after vaccination against COVID-19: A meta-analysis of self-controlled case series studies."" The response is a defense of the initial criticism to the paper regarding the validity of the inclusion of Ladapo´s paper.

Questionable robustness in the findings of a meta-analysis.

Marchand and colleagues conducted a meta-analysis examining COVID vaccine effects on all-cause and cardiac-related mortality. Findings aligned with previous research, showing no association with all-cause mortality. However, cardiac-related mortality exhibited a 6% increase post-vaccination.