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Canonical Source · systematic review
This page documents how this source is reused across Claim by Claim. A source can support, challenge, qualify or contextualize different claims; appearing here does not imply endorsement of every linked proposition.
Evidence context
Evidence roles describe what this source helps establish inside each Investigation. They are local to that use, not permanent labels attached to the publication itself.
Investigation
The 2023 Cochrane review found no clear pooled reduction in laboratory-confirmed respiratory viral infection from medical/surgical masks, while emphasizing adherence, heterogeneity and evidence limitations.
Much of the randomized evidence concerns respiratory viruses other than SARS-CoV-2.
Subject families