As we continue to endure the pain and burden of the COVID-19 pandemic with close to 16 million cases and more than , some reflection and acknowledgement is warranted, lest we forget and repeat our failures. Indeed, the associated with this pandemic demands critical and innovative thinking, especially as we move into phase III studies of COVID-19 vaccine candidates to confirm safety, and evaluate their efficacy and effectiveness, recognizing the of vaccine development including the fast-track process, referred to as "." Other critical concerns include the extent to which SARS-CoV-2, the virus that causes , and the role of in spreading the virus, amidst an expanding and terrifying pandemic, which is already eclipsing the historical images of the .
But foremost upon reflection, is the , in which and governmental authorities, for months, while there was explosive community spread of COVID-19 and an exponential death toll, emphatically communicated to the public, that mask-wearing in the conferred . They said the evidence just wasn't there, while noting that face masks should be reserved for healthcare workers. But as the world panicked, evidence emerged, and the headline now reads "CDC calls on Americans to wear masks to prevent COVID-19 spread." As well, in a complete reversal of position, the (World Health Organization) now advises that "masks can be used either for protection of healthy persons (worn to protect oneself when in contact with an infected individual) or for source control (worn by an infected individual to prevent onward transmission)."
But what constitutes evidence in this context? There has been an almost exclusive focus on evidence from experimental studies, specifically the (RCT), which is characterized as the "" of research, as it allows for the determination of causality. However, the reason such evidence is still lacking, should be obvious – the RCT is neither feasible nor appropriate for determining the effectiveness of mask-wearing in the community in protecting against COVID-19, and moreover, its use will be considered unethical in the context of a deadly pandemic. At the minimum, an would require manipulation of the intervention, by way of the researcher randomly assigning some members of the community to wear a face mask and others not to, and ensuring that both community groups are similar, based on key background characteristics, in other words, controlling for potential confounding factors.
An RCT may be theoretically perfect, but it is certainly not realistic in the context of mask-wearing and the COVID-19 pandemic. What is more relevant, meaningful, and available, is evidence from the observational research spectrum, . A is an observational study where an intervention such as mask-wearing was implemented by forces outside the researcher's control, such as a governmental mandate, and the outcome (level of COVID-19 infection) can be used to explore a specific research question, for example: Does mask-wearing in the community setting reduce the level of COVID-19 infection? The results can be evaluated for causal inference, using a common epidemiological model known as the .
Appreciating and using evidence other than from "true" experiments (i.e., an RCT) can be difficult especially in the health professions where the research culture is driven primarily by the hypothetico-deductive ; a closed or circular system of logic which can limit discovery and innovation. There is an urgent need for greater intellectual flexibility and curiosity.
Rossi A. Hassad, PhD, MPH, is an epidemiologist and professor at Mercy College, in Dobbs Ferry, New York. He is a member of the American College of Epidemiology and a fellow and chartered statistician of Britain's Royal Statistical Society.