Face mask use among individuals who are not medically diagnosed with COVID-19: A lack of evidence for and against and implications around public health recommendations.

IntroductionSince the beginning of the COVID-19 outbreak, public health professionals have been constantly making decisions on face mask use among individuals who are not medically diagnosed with COVID-19 or “healthy individuals” to limit the spread of COVID-19. While some countries have strongly recommended face masks for “healthy individuals”, other countries have recommended against it. Public health recommendations that have been provided to this population since the beginning of the outbreak have been controversial, contradicting, and inconsistent around the world. The purpose of this paper is to understand available evidence around the effectiveness or ineffectiveness of face mask use in limiting the spread of COVID-19 among individuals who have not yet been diagnosed with COVID-19 and most importantly, to understand the state of knowledge that the public health recommendations that have been provided since the beginning of the COVID-19 outbreak are based on.MethodsA systematic review was conducted to identify studies that investigated the use of face masks to limit the spread of COVID-19 among “healthy individuals”.ResultsNo studies were found, demonstrating a lack of evidence for and against face mask use suggesting implications around public health recommendations provided to “healthy individuals” since the beginning of the COVID-19 outbreak.ConclusionsThree and a half months into the COVID-19 outbreak (December 2019 – 2nd week of April 2020), there are no peer-reviewed scientific studies that have investigated the effectiveness or ineffectiveness of face mask use among “healthy individuals”. Yet, very strong public health recommendations have been provided on whether they should or should not wear face masks to limit the spread of COVID-19. A lack of scientific evidence heavily questions the basis of these public health recommendations provided at a very early, yet a crucial stage of an outbreak. This finding and a further look at public health recommendations conclude that there is a clear need for more concentrated research around face mask use among healthy individuals as well as public health recommendations that are evidence-based; precautionary in the absence of evidence; based on benefit-risk assessment; transparent; and globally aligned in order to provide the most successful guidelines during an infectious disease outbreak.