Few things are as controversial as wearing face masks in the community during the COVID-19 pandemic. The World Health Organization and the US Centers for Disease Control discouraged people from wearing masks in public. US Surgeon General Jerome Adams tweeted: “Seriously people — STOP BUYING MASKS!” Asian countries disagreed. The row continues even among medical professionals on both sides of the Atlantic. With millions of lives at stake, should people wear masks in public?
Surgical masks are designed to prevent transmission of disease droplets. This dreary piece of protective equipment is made of three layers consisting of a core melt-blown polymer sandwiched between non-woven fabrics. The melt-blown material acts as a filter to stop particles from entering or exiting the mask. These particles can include sprays, droplets, bacteria, and viruses. In fact, understanding the mode of transmission of SARS-CoV-2 lends credibility to staunch advocates of mask-wearing in public. The impish virus bides in secretions generated from our respiratory tracts, some deep down our lungs. It clings to droplets produced from an infected person’s cough or sneeze before traveling a few meters in the air. Droplets that reach a healthy person’s eyes, nose, or mouth release the virus particles into his or her respiratory tract where they replicate and cause illness. In science, efficacy is measured by data and statistics, and effectiveness by cost-benefit weighting. And what is known as evidence today may be supplanted by new evidence as our knowledge increases. Such is the beauty of science — the process of finding the truth. Scientists know (biological) plausibility alone falls short of deducing that “masks work” since 1965, when Sir Austin Bradford Hill proposed eight additional criteria to prove a causal relationship. Hence, hard evidence of mask-wearing to prevent COVID-19 spreading in the community was considered then to be lacking.
The COVID-19 pandemic invoked upsetting memories of SARS in 2003 in Asia across Hong Kong, Singapore, Taiwan, and parts of the Chinese mainland, during which the majority wore surgical masks in public. Some even wore N95 respirators. That epidemic raised hygiene awareness among Southeast Asians and it has since buried the taboo of facial coverage in the community. Many Japanese and Koreans now wear masks to prevent inhaling pollutants. Face-coverage styles abound, and no wearers are scorned for matching their masks with their apparel. As it is self-protective, wearing masks in the community is seen as a socially responsible act, especially when someone is ill. Unfortunately, few in Asia capitalized on research opportunities to investigate the effectiveness of mask-wearing in the community, among other public-health policies, in severing the chains of infection.
Social distancing and handwashing are well-proven. We should closely observe these practices among all the mask-wearing squabbles for our own benefit
Recently, Mark Loeb of McMaster University published an article in Influenza about the protective effects surgical masks and N95 respirators have on healthcare workers. He concluded that both were similar when it comes to preventing viral transmissions. The use of N95 respirators, specially designed equipment that blocks 95 percent of particles smaller than 0.3 microns, is warranted for circumstances in which aerosols are generated during invasive medical procedures such as intubation. WHO guidelines suggest healthcare workers and caregivers at home should wear surgical masks during routine care for patients. It is, however, a slippery slope to extrapolate the effectiveness of donning masks by healthcare workers to members of the public. Statisticians call it bias. Physicians and nurses learned the steps to take on and off personal protective equipment meticulously to minimize the chances of infection. Without such know-how, the general public may negate the benefits, not least when they contaminate their hands when they take off masks or when they reuse them. Expect people to be less vigilant about social distancing and hand hygiene as they have a false sense of security, said a health psychologist at University College London.
To address this heated debate, Professor Benjamin Cowling at the University of Hong Kong published an article in the latest issue of Nature Medicine, one of the journals with the highest impact factors. It revealed that 30 percent of droplets and 40 percent of aerosols shed by coronavirus-infected (bar SARS-CoV-2) patients could drop to zero had they donned a surgical mask. It does not help that personal protective equipment is suffering a global shortage. By inciting panic buying, physicians and nurses who work round-the-clock to save our loved ones and other patients may not get what they need. We are putting our bravest healthcare workers in danger in exchange for peace of mind. As responsible organizations for global health, the WHO and CDC had to draft policies that could benefit most people while factoring in equity and resource constraints. No longer. Surgical mask production has increased dramatically. 3M doubled its manufacturing capacity without raising the price. China has been exporting protective gear to America, Italy, and other countries in Africa. MIT and Cambridge University hosted hackathons to crowdsource solutions to mend global supply chains of health gear. The CDC has also changed its tone by endorsing homemade cloth facial coverings for the general populace — 30 percent to 50 percent of transmissions occur from asymptomatic carriers. How effective cloth coverings are against COVID-19, though, is unknown.
This crisis presents an opportunity for researchers to conduct studies ad hoc and post hoc. Questions left adrift include the complications and treatment of COVID-19 for pregnant women, the extent to which each public health policy made a dent on the transmission curve, and the ways in which culture, religion, and behaviors shape infections in society. Above all, social distancing and handwashing are well-proven. We should closely observe these practices among all the mask-wearing squabbles for our own benefit.
An absence of evidence should not preclude our personal freedom to take precautions. An absence of mask supplies should not diminish our social responsibility to ration scarce resources to those who need them most — poor countries and ethnic minorities deserve the same privileges we have convinced ourselves we are entitled to. As global supply chains are disrupted, our human bonds should strengthen. And our ends should transcend beyond self-means, just as our horizons should broaden across the world. We are all in this together.
The author is a licensed doctor in Hong Kong, and a Master of Public Health candidate at Johns Hopkins University.
The views do not necessarily reflect those of China Daily.
