The amount of misinformation around COVID is mind boggling. Unqualified physicians, some with blatantly embellished resumes, have inundated cable news and social media with false information. They have been very successful at convincing the public to reject recommendations from Infectious Disease doctors, Infection Control practitioners and public health experts. One example of the depth and extent of their misinformation is this widely held view - masks are useless at preventing the spread of COVID. But what does the medical literature have to say? Below, from UPTODATE, is the current state of the evidence based literature on this topic.
“Rationale — The primary objective for wearing masks in the community is to prevent transmission from individuals with infection by containing their respiratory secretions. Masks can also reduce exposure to SARS-CoV-2 for the wearer.
●Source control and transmission reduction – Multiple observational studies support the use of masks to provide source control and reduce transmission in the community [244,248-259]. In epidemiologic studies, government-issued mask mandates and high rates of self-reported mask-wearing have each been associated with decreased community incidence rates and, in some cases, decreased COVID-19 hospitalization rates [255,260-262]; lifting of universal mask mandates has conversely been associated with increased case rates [263]. In a meta-analysis of six observational studies, mask-wearing was associated with a 53 percent reduction in the incidence of COVID-19 [257]. Modeling studies have also suggested that high adoption of mask-wearing by the general public can reduce transmission, even if masks are only moderately effective in containing infectious respiratory secretions [264,265].
Nevertheless, efficacy of masks has been difficult to demonstrate consistently in clinical trials. In a meta-analysis of six trials that did not demonstrate reductions in laboratory-confirmed influenza or SARS-CoV-2 infection with wearing medical masks in the community (risk ratio [RR] 1.01, 95% CI 0.72-1.42), only two of those trials evaluated SARS-CoV-2 transmission [266]. One of those was a cluster-randomized trial in Bangladesh, in which villages that received free masks as well as behavioral and social interventions to promote masks had increased mask use (40 versus 14 percent in control villages) and, among those who received medical masks, an associated 11 percent relative reduction in SARS-CoV-2 seroprevalence that was not statistically significant (adjusted RR 0.89, 95% CI 0.78-1.01) [267]. The other trial, from Denmark, is discussed below.
●Prevent exposure – Mask-wearing in the community may protect the wearer; in several observational studies, consistent mask-wearing, particularly with medical masks or respirators, has been associated with a lower risk of infection [268-271]. In a report of 382 service members who were surveyed about personal preventive strategies in the setting of a SARS-CoV-2 outbreak on a United States Navy aircraft carrier, self-report of wearing a face cover was independently associated with a lower likelihood of infection (odds ratio [OR] 0.3), as were avoiding common areas (OR 0.6) and observing social distancing (OR 0.5) [268]. In a retrospective analysis of 1060 individuals identified by contact tracing following clusters of infections in Thailand, wearing a mask all the time was associated with a lower odds of infection compared with not wearing a mask; there was no significant association between wearing a mask some of the time and infection rate [269]. In contrast, a randomized trial from Denmark did not identify a decreased rate of infection among individuals who were provided with surgical masks and advised to wear them when outside of the house for a month (1.8 versus 2.1 percent among individuals who were not given masks or the recommendation) [272]. However, the low rate of community transmission (as reflected by the low overall infection rate) may have made it difficult to detect a meaningful difference. Additionally, much SARS-CoV-2 transmission occurs in the household, where masking is seldom practiced or may be used too late after a sick household contact enters the home.
●Filtration efficacy – Filtering facepiece respirators (FFR) have the highest filtration efficacy. In the United States, the prototypical FFR is the N95 respirator, which filters at least 95 percent of 0.3 micrometer particles. Medical masks have lower filtration efficacy, which depends on how closely the mask lies against the face. In one study, medical masks with ties versus ear loops filtered 72 and 38 percent of particles, respectively (approximately 0.02 to 3.00 micrometers) [273]. Other strategies to improve the fit of a medical mask, such as using a cloth mask over it or knotting the ear loops to eliminate gaps, also appear to increase filtration efficacy [274]. Studies on the filtration efficacy of fabrics suggest that certain fabrics (eg, tea towel fabric [termed dish towel fabric in the United States], cotton-polypropylene blends), particularly when double-layered, can approach the filtration efficacy of medical masks [244,275-277]. In an experimental model, universal masking with a three-ply cotton mask was shown to substantially reduce aerosol exposure [239]. Tight-weave fabric, two or more layers, and a tight fit are essential for adequate filtration.”
Why the confusion?
Quality evidence is hard for the lay public to access. As physicians we have access to sources like UPTODATE which is not inexpensive. The average person does not. That leaves the public vulnerable to misinformation. If you don’t know where to get correct information you turn to the wrong sources such as cable news and social media. Nearly everything you hear on these sources about COVID is wrong. How is the public to know that? How can you discern the difference between information and misinformation? You can’t. Unless you have sufficient training in clinical medicine, clinical infectious diseases and critical appraisal of the medical literature, it is virtually impossible to spot the fake Gucci handbag of COVID misinformation. That provides the opening for unqualified experts to sell misinformation.
Hi Mike! More of your bullshit today?