Facemasks in the COVID-19 era: A
health hypothesis
Autor: Baruch Vainshelboim
Estudio revisado por pares y publicado en NCBI (National Center for Biotechnological
Information).
El Centro Nacional de Información Biotecnológica (NCBI) forma parte de la Biblioteca Nacional de
Medicina de Estados Unidos, una división de los Institutos Nacionales de Salud. Está aprobado y
financiado por el gobierno de los Estados Unidos.

Abstract
Many countries across the globe utilized medical and non-medical facemasks as nonpharmaceutical intervention for reducing the transmission and infectivity of coronavirus disease2019 (COVID-19). Although, scientific evidence supporting facemasks’ efficacy is lacking,
adverse physiological, psychological and health effects are established. Is has been
hypothesized that facemasks have compromised safety and efficacy profile and should be
avoided from use. The current article comprehensively summarizes scientific evidences with
respect to wearing facemasks in the COVID-19 era, providing prosper information for public
health and decisions making.

Introduction
Facemasks are part of non-pharmaceutical interventions providing some breathing barrier to the
mouth and nose that have been utilized for reducing the transmission of respiratory pathogens
[1]. Facemasks can be medical and non-medical, where two types of the medical masks
primarily used by healthcare workers [1], [2]. The first type is National Institute for Occupational
Safety and Health (NIOSH)-certified N95 mask, a filtering face-piece respirator, and the second
type is a surgical mask [1]. The designed and intended uses of N95 and surgical masks are
different in the type of protection they potentially provide. The N95s are typically composed of
electret filter media and seal tightly to the face of the wearer, whereas surgical masks are
generally loose fitting and may or may not contain electret-filtering media. The N95s are
designed to reduce the wearer’s inhalation exposure to infectious and harmful particles from the
environment such as during extermination of insects. In contrast, surgical masks are designed
to provide a barrier protection against splash, spittle and other body fluids to spray from the
wearer (such as surgeon) to the sterile environment (patient during operation) for reducing the
risk of contamination [1].
The third type of facemasks are the non-medical cloth or fabric masks. The non-medical
facemasks are made from a variety of woven and non-woven materials such as Polypropylene,
Cotton, Polyester, Cellulose, Gauze and Silk. Although non-medical cloth or fabric facemasks
are neither a medical device nor personal protective equipment, some standards have been
developed by the French Standardization Association (AFNOR Group) to define a minimum
performance for filtration and breathability capacity [2]. The current article reviews the scientific
evidences with respect to safety and efficacy of wearing facemasks, describing the
physiological and psychological effects and the potential long-term consequences on health.

Hypothesis
On January 30, 2020, the World Health Organization (WHO) announced a global public health
emergency of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) causing illness
of coronavirus disease-2019 (COVID-19) [3]. As of October 1, 2020, worldwide 34,166,633
cases were reported and 1,018,876 have died with virus diagnosis. Interestingly, 99% of the
detected cases with SARS-CoV-2 are asymptomatic or have mild condition, which contradicts

1