Understand sources

re: "Masked efficacy" (BP, PostBag, December 10, 2022) 

Dear editor,

I've been loath to join the lusty debate about the merits and demerits of various Covid-related policies, but Michael Setter's latest requires a response. Intrigued by his claims regarding it, I added Mr. Setter's cited source from The Annals of Internal Medicine to my morning coffee reading routine. Having read it, I was perplexed. The paper "Medical Masks Versus N95 Respirators for Preventing Covid-19 Among Health Care Workers" (2022, DOI: 10.7326/M22-1966) does not say what Mr Setter reports it saying, namely, that Loeb et al.'s paper "shows unequivocally that not even well-fitted N95 masks demonstrate any effectiveness in preventing Covid-19 transmission or infection." Quite the contrary. What it in fact says, to quote the authors' words, is that "In conclusion, among health care workers who provided routine care to patients with COVID-19, the overall estimates rule out a doubling in hazard of RT-PCR–confirmed COVID-19 for medical masks when compared with HRs of RT-PCR–confirmed COVID-19 for N95 respirators." This conclusion is consistent with what the authors say they set out to investigate. 

I am left wondering, therefore, how Mr Setter came to claim for it something so very far from what his cited source in fact says. Did he read the paper and not understand its plain content? Did he not actually bother to read it, instead reporting someone else's misunderstanding or false claim for the research? Or is there some other explanation for the obvious mismatch between Mr Setter's account of that the paper says about the value of masking and what the paper itself says on that topic? 

I like to see writers citing reputable sources in support of their ideas, but it's important to correctly understand and accurately report the ideas and information in those sources. 

 Felix Qui 

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The above letter to the editor is the text as submitted by Felix Qui to the Bangkok Post.

The text as edited was published in PostBag on December 17, 2022, under the title "Understand sources" at https://www.bangkokpost.com/opinion/postbag/2462565/the-real-threat-