We only looked at studies published by the United States National Institute of Health [NIH] or the United States Center for Disease Control and Prevention [CDC]. This is an agency of the United States Department of Health and Human Service responsible for biomedical and public health research. The CDC is an agency of the United States Department of Health and Human Services whose goal is to protect public health and safety through the control and prevention of disease, injury, and disability in the US and internationally.
There are many other studies available online and they all seem to support the same conclusions. The oldest mask study that we found was conducted by the California State Department of Health in 1919. It found no real difference in the spread of the Spanish Influenza when comparing a California city with mandatory mask-wearing to the city of Boston, MA where a majority of people were not wearing masks. However, more recently a variety of media outlets have attempted to come up with reasons why that study was flawed. Yet, one hundred years later, researchers are still coming to the same conclusion found by the California State Department of Health in 1919.
Anthony Fauci, head of the National Institute of Allergy and Infectious Diseases [NIAID] division of the NIH, himself stated on 60 Minutes that masks should not be worn in public. He went on to say that mask-wearing could make you more likely to become sick.
Exercising with facemasks may reduce available Oxygen and increase air trapping preventing substantial carbon dioxide exchange. The hypercapnic hypoxia may potentially increase acidic environment, cardiac overload, anaerobic metabolism and renal overload, which may substantially aggravate the underlying pathology of established chronic diseases. Further contrary to the earlier thought, no evidence exists to claim the facemasks during exercise offer additional protection from the droplet transfer of the virus.
We did not find evidence that surgical-type face masks are effective in reducing laboratory-confirmed influenza transmission, either when worn by infected persons (source control) or by persons in the general community to reduce their susceptibility.
Hand hygiene is a widely used intervention and has been shown to effectively reduce the transmission of gastrointestinal infections and respiratory infections. However, in our systematic review, updating the findings of Wong et al., we did not find evidence of a major effect of hand hygiene on laboratory-confirmed influenza virus transmission.
We studied the effect of surface morphology of locally available face masks on their PM filtering efficiency. Filtering efficiency of CM [Cloth Masks] for ambient PM10 was poorer than in SM [Surgical Masks]. The poor efficiency was due to the presence of larger sized pores. Our study also demonstrated that washing and drying cycle deteriorates the filtering efficiency due to change in pore shape and clearance. We also found that stretching of the CM surface alters the pore size and potentially decreases the filtering efficiency. The findings of this study suggest that CM are not effective, and that effectiveness deteriorates if used after washing and drying cycles and if used under stretched condition.
Respiratory pathogens on the outer surface of the used medical masks may result in self-contamination. The risk is higher with longer duration of mask use (> 6 h) and with higher rates of clinical contact.
Wearing a surgical mask modifies significantly and clinically dyspnea [diffult or labored breathing – Oxford Dictionary] without influencing walked distance.
Breathing through N95 mask materials have been shown to impede gaseous exchange and impose an additional workload on the metabolic system of pregnant healthcare workers, and this needs to be taken into consideration in guidelines for respirator use. The benefits of using N95 mask to prevent serious emerging infectious diseases should be weighed against potential respiratory consequences associated with extended N95 respirator usage.
None of the studies we reviewed established a conclusive relationship between mask/respirator use and protection against influenza infection.
Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds.
Wearing an N95 mask for 4 hours during HD significantly reduced PaO2 and increased respiratory adverse effects in ESRD patients.