Masks work. Especially his N95 mask of respirator type.
Amid the ongoing pandemic and outbreaks of influenza and RSV caused by airborne viruses, the debate over the virus-blocking power of masks is one of the prime folly of the COVID era. Surprisingly, despite decades of proven efficacy, some of the disagreements stem from the medical field itself misusing science and endangering lives. It comes from the department.
Most recently, a Cochrane review, which systematically evaluated multiple randomized controlled trials, caused headlines after it claimed there was insufficient evidence that masks protect against transmission of many respiratory viruses. Not for the general public, healthcare professionals, or anyone else. “There is absolutely no evidence that they make a difference,” the lead author said in a media interview. It brought an unusual accusation.
It wasn’t the first time something like this had happened. Late last year, a randomized controlled trial claimed that N95 respirators are no match for medical (or surgical) masks for healthcare workers. The scientist, engineer, and occupational health and safety expert highlighted the flaws in this study (see its comments section), but these two episodes of his point to a larger underlying problem. Whether these types of trials are suitable for testing how much physical interventions such as masks reduce viral transmission. .
Medical claims of exclusive “property” over mask science as they are used during a pandemic ignore the fact that masks represent a well-understood engineering solution. The request to reject this evidence reflects a failure to recognize and respect the multidisciplinary expertise that has undermined the response to the global pandemic.
Placing randomized trials on top of other types of research, such as observational, laboratory, and modeling studies, has hampered the response to COVID. A randomized trial approach that allows a small number of studies to cancel a vast amount of research from other fields has no scientific basis.
Prioritizing these trials for medical decision-making started with good intentions. In the 1980s, experts wanted to successfully integrate scientific knowledge into medicine. Subsequent decisions varied widely among practitioners based on different readings, experience, and education. Improving medical decision-making to be more reproducible, consistent and evidence-bound marked the commendable birth of the evidence-based medicine movement.
This effort included establishing a “hierarchy of evidence”, the idea that some types of evidence are more useful to medical decision makers than others. Observational studies are at the bottom of the pyramid, randomized trials are in the middle, and a systematic review of these trials at the top, where researchers collectively reviewed the results of several clinical trials and is being conducted at Cochrane. make a broader and more definitive statement, such as review.
Randomized trials underlie much of medical research because the human body is messy. Chemicals that are effective in laboratories and animal models may be useless or even harmful once in the human body. Alternatively, it may occur only in some people, depending on genetics, environment, or underlying disease. Randomizing trial participants averages out that noise and reduces bias. Comparing treatment outcomes between randomly selected groups holds promise for isolating effects and making these trials the ‘gold standard’ of medical research. However, it is often time consuming, requires many participants (especially if the expected difference is small) and a large budget. Even the most rigorous trials cannot determine whether treatment was effective with another protocol.
Because these trials can be so narrowly focused and controversial, systematic compilations and reviews, such as those produced by the Cochrane organization, make medical decisions faster and easier. Of course, relying on such reviews trades the convenience over the rigors of digesting each study to gain real knowledge. This is one concern for them.
For masks, are randomized trials a good way to evaluate basic engineered safety systems in the first place? The oft-quoted randomized parachute trial is an old joke. why is it so hilarious? What do engineers know that doctors don’t?
In many scientific fields, randomized trial methods are fundamentally inappropriate. It’s like mowing a lawn with a scalpel. If something can be measured directly or modeled accurately and accurately, there is no need for complex and inefficient trials that put participants at risk. Engineering, perhaps the most “real world” discipline, does not conduct randomized trials. The required knowledge is well understood. Everything that moves us, cleans our air and water, and keeps satellites in orbit, from highways to ventilation systems, thrives without needing them. This includes many medical devices. When failures such as plane crashes or catastrophic bridge collapses occur, they are recognized and systematically analyzed to prevent recurrence. This contrasts with the lack of attention to public health failures in this pandemic.
“Will a mask protect me from an aerosolized virus?” or “Will this seat belt keep me from jumping out of a window in an accident?” is a different type of question. It would be a mistake to lock engineering and natural sciences at the bottom of the hierarchy of evidence on the same level as expert opinion. As with seat belts, it is important whether people use masks properly, but no randomized trial has concluded that seat belts “do not work.” It’s a really inefficient way to assess specific directives and incentives for proper use.
Respiratory protection, a well-understood technology, has been validated for decades by codified standards for protection against viruses and bacteria (NIOSH in the United States, CSA in Canada). Mining, biomedical research, chemical processing, pharmaceutical manufacturing, and many other industries follow these laws and standards around the world. Without exaggerating, without the need for randomized trial evidence, millions of people trust their lives in the effective “real world” science of respiratory health.
Therefore, when evidence supports N95 respirators or better, ideally two-way masking, it is deeply concerning that prominent medical personnel misrepresent the protection offered by masks.
Health policy makers failed to learn the lessons of the 2003 SARS-1 outbreak, which has been exposed again in the current pandemic. New pathogens require preventive approaches, including airborne respiratory protection, until proven otherwise. With millions of people dead and the personal and economic toll from the long-lasting COVID-19 pandemic, it will continue to inflict tremendous damage if we fail to adjust now.
It’s never too late to improve.
This is an opinion and analysis article and the views expressed by the author or authors are not necessarily Scientific American.
