In other words, the journal editors noted, "the study examined the effect of recommending mask use, not the effect of actually wearing them."
There's also the possibility that people who wore masks felt a false sense of security and let down their guard in other ways that increased their risk of infection.
Given these various shortcomings, you might suspect the Annals of Internal Medicine editors were tempted to reject the study so it wouldn't wind up in the hands of increasingly vocal opponents of mask mandates. They don't blame you for wondering — indeed, they anticipate this question in their editorial.
"With fierce resistance to mask recommendations by leaders and the public in some locales, is it irresponsible for Annals to publish these results, which could easily be misused by those opposed to mask recommendations? We think not," wrote Dr. Christine Laine, the journal's editor in chief, along with Dr. Eliseo Guallar, the deputy editor for statistics, and Dr. Steven Goodman, a former senior statistical editor for the journal.
Burying the findings of a well-conducted study that didn't turn out as expected would be worse, they wrote.
"We need to gather many pieces of evidence to solve the puzzle of how to control the SARS-CoV-2 pandemic," they explained. "For this reason, we thought it important to publish the findings and carefully highlight the questions that the trial does and does not answer."
Frieden and Cash-Goldwasser agreed that researchers still have work to do.
But in the meantime, they wrote, the bottom line is clear: "If everyone wears a mask when near others, everyone is safer."(c)2020 Los Angeles Times Distributed by Tribune Content Agency, LLC