A large study run in Bangladesh claimed that surgical masks, but not cloth masks, reduced symptomatic SARS-CoV-2 infections" by 0.08% (ARR), and only in people over 50. But a subsequent re-analysis of the study by statisticians found that there was in fact no benefit at all.

People with chronic respiratory, cardiac, or other medical conditions that make breathing difficult should check with their health care provider before using an N95 respirator because the N95 respirator can make it more difficult for the wearer to breathe.

Despite not being regulated, there are ways for these brands and their manufacturers to increase their trustworthiness, like FDA registration or inclusion in the FDA's now-defunct emergency use authorization (EUA), which it passed in 2020 to help medical workers choose KN95 masks.

Miller also previously told us that the list of KN95 models the FDA specifically approved in its April 2020 emergency use authorization n95 masks with ear loops is one of the best resources to use when sourcing the respirators, even after the FDA stopped updating the list in 2021.