By Vinicius Sales
In a letter sent to the National Health Surveillance Agency (Anvisa) this Monday (13), the Federal Council of Medicine (CFM) admitted that the masks used to prevent covid-19 infection are ineffective against the disease writes Brasil Sem Medo in its latest report.
“Finally, there are already studies of great scientific relevance that demonstrate the inefficiency of such a measure in reducing the spread of SARS-CoV-2.”
“Such investigations present a variety of methods, data sources, and forms of analysis that require detailed assessments far beyond the mere reading of titles and abstracts or even the use of automated tools,” says the CFM in the document obtained exclusively by Brasil Sem Medo.
The letter highlights that the masks can contain large covid-19 particles but points out that there is strong evidence that the finer particles are not prevented by the masks since “they tend to remain in the air for a long time and travel relatively long distances.”
The CFM also points out that the lack of uniformity of masks available to the population affects the “eventual efficacy in a very relevant way due to the different types, materials, formats, and quality, as well as their use, adjustment and cleaning, and the environment involved.”
The autarchy also lists studies favorable and unfavorable to mask use to support its conclusion.
The document cites a meta-analysis published by the largest evidence-based medicine center on the planet, the Cochrane Library.
The study looked at 12 trials, comparing medical/surgical masks with not wearing masks to prevent the spread of viral respiratory diseases (two trials with healthcare workers and 10 in the community).
The CFM document citing the study says:
“Use of masks in the community likely makes little or no difference in the outcome of influenza-like illness (ILI)/Covid-19-like illness compared with no use of masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09″; 9 trials, 276,917 participants; evidence of moderate certainty).”
“Wearing masks in the community probably makes little or no difference in laboratory-confirmed influenza/SARS-CoV-2 outcomes compared with not wearing masks (RR 1.01, 95% CI 0.72 to 1.42; 6 trials, 13,919 participants; evidence of moderate certainty).”
“Harm was measured rarely and poorly reported (evidence of very low certainty).”
The autarchy also exposes that “the conclusions for inefficiency are based on a meta-analysis of randomized trials (RCTs). The masks make almost no difference; the results have no statistical significance, and the point estimates of efficacy are very close to zero.”
Furthermore, the study scores no difference in efficacy between surgical masks and N95 – which dismantles the narrative propagated over the past two years that this mask would be more effective.
“Use of N95/P2 respirators compared with medical/surgical masks likely makes little or no difference to the objective, more accurate outcome of laboratory-confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; 5 trials, 8407 participants; evidence of moderate certainty).”
“Restricting aggregation to healthcare workers made no difference to overall outcomes. Harm was poorly measured and reported, but discomfort with wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies (very low certainty evidence),” the study adds.
The CFM also criticizes the measures taken by public officials who used the supposed efficacy to make masks mandatory in several places.
The autarchy cites Anvisa‘s stance as an example.
“Therefore, there is no scientific evidence that the use of masks in a trivialized and widespread manner in the community has any impact on the transmission of Covid-19 or even the reduction of illness.”
“This includes measures such as those of the National Health Surveillance Agency, which has been requiring passengers, crew, and airport employees to wear masks when entering the so-called ‘airside’ of the airport.”
“Besides having no evidence of protection, there is evidence of harm to the health of crew members, passengers, and the environment,” concludes the CFM.
With information from Brasil Sem Medo (BSM)