The latest edition of the Cochrane Review meta study on masking and other interventions is, sadly, little more than a rehash of old studies that tells us nothing new about the efficacy of masks. The first version was published in 2006, the fifth version completed in January 2020 (but was held up until Nov. 2020), while the most up-to-date 2023 version contains only 2 new studies on Covid masking (the Bangladesh study, Abaluck 2022, and the Denmark study, Bundgaard 2021) and contains no original research of its own.
The Cochrane study, and Bret Stephens’ NY Times editorial endorsing the shaky conclusions of its lead author, are essentially propaganda pieces. I don’t know whether masking works, or what kind of masks are truly effective, but their effectiveness is now undeniably a crucial question to be studied in light of Covid-19 and Gain-of-Function research.
Through such biological research, which is nothing less than a new arms race, novel pathogenic viruses may be easily synthesized and represent a substantially greater threat to humans than even nuclear weapons, whose blasts have a limited predictable range, whereas viruses can spread uncontrollably to every human on the planet. Thus, it is critical to understand which practical measures can be taken by ordinary people during pandemics to protect themselves from new lethal biological agents created inadvertently in labs for defensive use, or perhaps even deliberately for offensive purposes.
Since the Cochrane Review is a meta-analysis, it can be informative to read what the actual researchers wrote and thought instead of relying on the meta-reviewers. Here are excerpts from most of the primary studies cited (although some weren’t convinced, most supported masks):
In favor of their use, I would also add “Respiratory virus shedding in exhaled breath and efficacy of face masks” (Leung, 2020), “Effectiveness of vaccination and wearing masks on seasonal influenza in Matsumoto City” (Uchida 2017), and the mysteriously withdrawn study of Chinese bus passengers described in the South China Morning Post (“Coronavirus can travel twice as far as official ‘safe distance’ and stay in air for 30 minutes“) in which reportedly none of the passengers who wore face masks were infected (original study here).
Again, I’m not sure if masks work or not. I find @Kevin_McKernan‘s assertion that masks act as droplet nebulizers enhancing the infectiousness of viral aerosols very plausible. But where’s the research for it on C19? Medical scientists do not seem to want to know.
On the other hand, in favor of masking, it is hard to find examples of super-spreading events where participants were required to wear masks. And countries where masking was culturally accepted seemed to do very well in the beginning stages of the pandemic, when it was most important.
Here in April 2020, there was a rising fear that basic services needed to survive might close, but fortunately, groceries and other essential businesses did not shut down completely for lack of workers, a possible result of masking. Despite common impressions to the contrary, the importance of masking was not primarily for customers, but for the people working in such spaces who were often being exposed to hundreds of potential carriers every day.
One might suppose there is little point to masking in a crowded internal space if it reduces the airborne viral load from say, 10 million virions (fully formed virus bodies which can replicate) to 8 million virions. (I’m still gettin’ sick, right?) However, if such reductions are achieved consistently, they can have a major impact on reducing the burden of care at hospitals which (in my state) each have about 80,000 inhabitants to potentially care for at any one time. No one wants them all coming in at once.
Just as importantly, hospitals continued to function and did not shut down even as more and more staff became infected, and the state of New Jersey faced down a 3% infection fatality ratio. Perhaps masks provided only a false sense of security, but for those first few months when almost nothing was known about the virus or how best to treat it, they provided a way for society to function.
Promoting the use of masks was not the fault of public health officials. What was their fault, however, was to force people to wear masks for obvious political reasons, rather than allowing individuals, organizations, and businesses to decide for themselves what was best. They failed to promote research or provide informed guidance. We got slogans instead. Yet they continue to avoid the kind of research needed to provide answers to these pressing questions, such as:
What is the TCID50, or rough number of Covid-19 virions needed to infect the average person? (Keep in mind this number is not the same as viral “particles” which are simply pieces of matter containing traces of viral DNA, and not necessarily replicable virions per se.) We don’t know. It could be 1, which would be scary and difficult. It could be 500, or 2000, but one can’t devise a good policy of mitigation until that number is known. And of course the number will vary somewhat from variant to variant. A few more questions:
- How much does masking reduce infectious viral aerosols in a typical indoor space?
- Does masking greatly reduce the infectiousness of super-spreaders?
- Are we really sure that transmission is through aerosols and airborne droplets?
- Does H2O evaporated from water droplets containing virions also contain virions, or is it pure distilled water only?
- How many C19 virions are contained in the typical aerosol droplet breathed out by an average infectious human? How many of these virions in aerosols and droplets do masks really catch?
- How much does casual exposure to non-infectious amounts of the virus before getting sick help our immune system beat the disease after we get sick?
- And of course, how effective are various types of masks against C19, and can new more effective masks be created?
It is not enough to study mandates alone as an intervention when governments were only just following what their own populations were already doing, as a pretense of maintaining authority. Scientists must also study the mechanistic behavior of Covid viruses at the individual biological level, and tie that in with the type of masks, enclosures, air conditions, and policies to determine what really works, and what doesn’t.
In the end, I do agree with the Cochrane Review study’s authors who wrote, in contradiction to its lead author:
The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions. There were additional RCTs during the pandemic related to physical interventions but a relative paucity given the importance of the question of masking and its relative effectiveness and the concomitant measures of mask adherence which would be highly relevant to the measurement of effectiveness, especially in the elderly and in young children.
There is a need for large, well‐designed RCTs [randomized controlled trials] addressing the effectiveness of many of these interventions in multiple settings and populations, as well as the impact of adherence on effectiveness, especially in those most at risk of ARIs [acute respiratory infections].