How Misinformation Tries to Discredit the Science Behind Masking

Public health is literally under attack. The recent shooting at the CDC is a testament to the impact that disinformation has had on the public and how a large segment of our society is not only shunning public health advisements but is actively trying to undermine them. It is unlikely that there will be widespread vaccine acceptance, making it of utmost importance for one to protect oneself to the highest degree possible.

Thus, it is with some trepidation that I write this commentary regarding the misinformation and need for masking during outbreaks of dangerous viral pathogens. The misinterpretation of scientific evidence supportive of masking has hindered mask acceptance. Similar misrepresentations can be found that are directed at the entire public health infrastructure, leading to public mistrust and even anger focused upon public health officials.

Overriding principles regarding the impact of both user compliance and exposure time on the benefits of masking were put forward by Vinay Prasad, MD, MPH, the current US Food and Drug Administration (FDA) Director of the Center for Biologics Evaluation and Research. He stated: “…poor compliance can thwart bio plausibility.” And “…prolonged exposure time can thwart a marginal change in particle exposure.”

Dosage is, thus, important. A virus does not have eyes or the ability to move.The encounter between a cell and its receptor is entirely random, similar to a battlefield where a single blind gunman tries to hit a target. It is unlikely to happen.But with a million gunmen, 1 may hit its mark.
 
A study that demonstrates the importance of exposure time and masking on SARS-CoV-2 cases was published by Zhao and colleagues. They studied airline passengers and observed a 4.66 to 25.93 increase in rates of infection for those on medium and long flights, respectively, compared to those taking short flights. They observed no transmission on long flights where masking was enforced, and there was a 1.53 times increase in SARS-CoV-2 transmission for every 1 hour of flight duration.
 
This effect was tabulated by the Colton and Rockefeller Foundations, which found that, on average, if one did not wear a mask, a 15-minute exposure to the virus was needed to become infected. This exposure time increased to 1 hour with universal use of a surgical mask, 6.25 hours with a non-fit-tested N95 mask, and 25 hours with a fit-tested N95 mask.

Some have viewed masking as a standalone preventative measure, scoffing at layered approaches. A layered approach means you simultaneously use more than 1 preventative strategy. Layered strategies are recommended for almost every disease in medicine, from cancers to simple upper respiratory infections. The home remedy for a cold, consisting of keeping warm, resting, Vitamin C, and chicken soup, is an example of the public embracing a layered approach. Certainly, enacting multiple strategies to prevent the spread of a dangerous virus should not be viewed as unwarranted.

The effectiveness of masking was brought into question by a large Cochrane review article by Jefferson et al. Many have used this article as justification to shun masking, despite the article’s published caveat that “relatively low numbers of people followed guidance about wearing masks….” and that several articles had what appeared to be design flaws. For example, the article by Lobe et al (2009) stated that the “use of such a surgical mask was required by the Ministry of Health and Long-Term Care when providing care to or when within 1 m of a patient”.Many felt that a more stringent requirement for when to mask would be needed to prevent transmission effectively.
 
However, other review articles found masking to be effective, including a systematic review by Leah Boulos et al, and an extensive review of over 100 research articles and reviews by Trisha Greenhalgh et al. The study by Greenhalgh et al concluded that masks are effective if “correctly and consistently worn,” and that respirators (ie N95 masks) were more effective than medical or cloth masks, and that community mask mandates were effective in reducing transmission.
 
Because of these seemingly conflicting results, many, including Prasad, have called for more high-quality RCTs (randomized controlled trials). However, to be considered high-quality, an RCT must be double-blinded. Otherwise, unwanted biases may affect the results. For example, those wearing masks may be more willing to see infected patients and thus have more exposures than unmasked individuals. Facilities may be less willing to invest in upgrading their ventilation system and air quality if staff are already wearing masks. Unfortunately, it is challenging to design a masking study where the subject is unaware that they are wearing a mask.
 
Ethical problems are also created when designing randomized controlled studies that incorporate a control group without an intervention that is likely to be beneficial. Clinical equipoise would not be achieved. This is underscored by the parachute RCT parody, which was published by Smith and Pell in the British Medical Journal in 2003.There has never been an RCT showing the effectiveness of parachutes, but how can one ethically conduct such a study? Who would be in the control group?

However, the lack of RCTs has caused some to cast doubt on the effectiveness of masking.Prasad has stated. “You can’t have a double standard for evidence. Masks and ivermectin both have no evidence to justify them, and both ‘don’t work’ until that evidence is marshaled. You can’t say ivermectin doesn’t work, but masks might.”

However, comparing the evaluation of public health strategies to that of drug trials is comparing apples and oranges. Drug trials require compliance as little as 5 to 10 minutes per day when one takes the drug. Clinical trials involving public health strategy require compliance for 8 hours a day, at least 5 days a week. Drug trials can be easily double-blinded, but this is extremely difficult, if not next to impossible, when designing trials to evaluate public health strategies, such as those involving masking. Biases are frequently present and often permeate non-blinded public health trials.

Well-designed studies do exist for masking, but they are not blinded. In Bangladesh, a large NIH community-level study was conducted by the Innovations for Poverty Action, along with Yale and Stanford Universities. The study involved over 340,000 adults and evaluated the effect of mask distribution (surgical and cloth masks) and education. Both arms masked, which would be expected to blunt the results. The rate of proper mask wearing in the study’s arms was 13.3% to 42.3%, or a 29-percentage point difference. Surgical masks resulted in an 11% reduction in symptomatic seroprevalence.One would expect the reduction to be much higher if the intervention arm had 100% masking and the control arm 0%, and N95 masks were used.

There have also been multiple studies that have reported a beneficial effect of masking requirements in schools. A large study published by Tori Cowger, et al, in the NEJM found:“Among school districts in the greater Boston area, the lifting of masking requirements was associated with an additional 44.9 Covid-19 cases per 1000 students and staff during the 15 weeks after the statewide masking policy was rescinded.”

However, ivermectin has been found to be ineffective in at least 3 double-blinded randomized controlled clinical trials. A large trial evaluated outpatients with mild-to-moderate COVID-19 and found no benefit for ivermectin compared to placebo. Other researchers have found that ivermectin was not effective in preventing hospitalization from COVID-19, and finally, that ivermectin did not improve clinical outcomes in patients with mild COVID-19.
 
Although the literature appears to be conflicting, it should be remembered that in today’s world of paper mills, almost any position can be supported by peer-reviewed research, and that it is nearly impossible to conduct high-quality randomized trials that are designed to validate public health strategies.
 
In the case of mask effectiveness, there are 2 critical observations.First, a possible reason why so many trials in health care settings have not been able to show a beneficial effect is that the viral dosage and exposure times are too high and too long, which may lead to contracting the illness with even 1 protocol lapse. Unfortunately, clinical trials in health care settings often have suboptimal compliance.
 
Thus, using a surgical or even an N95 mask as the primary strategy in a health care setting may not be adequate. Other strategies to lower viral dosage and contact with airborne pathogens are needed. This includes clean air and increased ventilation.

However, during a pandemic, advising the public to wear an N95 mask for short-term exposures, such as going into a restaurant to pick up a takeout order, is a sound strategy.
 
We must not discard interventions because they alone do not offer 100% protection. No public health intervention can achieve this goal. Not vaccinations, not clean air, and not masking. Instead, we must strive to lower the viral dosage a person is exposed to and to layer on additional protection if the initial protection is inadequate.