“That review, published by the Cochrane Library, an authoritative collection of scientific databases, analyzed 18 randomized controlled trials (RCTs) that aimed to measure the impact of surgical masks or N95 respirators on the transmission of respiratory viruses. It found that wearing a mask in public places “probably makes little or no difference” in the number of infections.”
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“The authors suggest several possible explanations for these results, including “poor study design,” inconsistent or improper mask use, “self-contamination of the mask by hands,” “saturation of masks with saliva,” and increased risk taking based on “an exaggerated sense of security.””