Does a mask work? It's a question recently posed by the Danish newspaper Berlingske,[i] and one that would seem to demand an answer from scientists and public health officials alike. Yet, despite mask mandates existing in 34 U.S. states and the District of Columbia,[ii] there's shockingly little hard data about whether or not they slow the spread of infectious disease.

Researchers from Denmark wanted to change that, conducting what may be the only randomized trial[iii] to determine if masks actually protect against COVID-19,[iv] but multiple medical journals have refused to publish the findings.

Thomas Benfield, a researcher at the University of Copenhagen and one of the study's lead authors,[v] was asked when it would be published. Former New York Times reporter Alex Berenson published Benfield's emailed response on Twitter, which is simply: "As soon as a journal is brave enough …"[vi]

What Does the Danish Mask Study Reveal?

Speaking to Nature in October 2020, Benfield said his team wasn't yet ready to share the study's results.[vii] In truth, three medical journals -- The Lancet, the New England Journal of Medicine and the Journal of the American Medical Association -- have refused to publish the study, leading to speculation that it reveals a message that goes against the status quo.