Amid an ongoing pandemic and outbreaks of influenza and RSV caused by airborne viruses, arguing over the virus-blocking power of masks remains one of the COVID era’s signature follies. Disconcertingly, despite decades of evidence of their efficacy, some of the disagreement comes from a few in the medical field itself, misusing science and endangering lives.

Most recently a Cochrane review, which systematically assesses multiple randomized controlled trials, provoked headlines after claiming a lack of evidence that masks prevent transmission of many respiratory viruses. Not for the public, health care workers, or anyone. “There is just no evidence that they make any difference,” the lead author said in a media interview. This brought an unusual chastisement from the Cochrane Library’s editor-in-chief, who stated it was “not an accurate representation of what the review found.”

That wasn’t the first time something like this has happened. Late last year, a randomized controlled trial claimed that N95 respirators were no better than medical (or surgical) masks for health care workers. Whereas scientists, engineers and occupational health and safety experts highlighted flaws (see its comments section) in the study, these two episodes point to a bigger fundamental question: whether these types of trials are suitable to test how well physical interventions like masks reduce viral transmission.