Quick Links:
Studies and Reviews:
Unmasking the surgeons: the evidence base behind the use of facemasks in surgery - Journal of the Royal Society of Medicine - "Overall there is a lack of substantial evidence to support claims that facemasks protect either patient or surgeon from infectious contamination."
Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings—Personal Protective and Environmental Measures - (CDC) - "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."
Physical interventions to interrupt or reduce the spread of respiratory viruses. Part 1 - Face masks, eye protection and person distancing: systematic review and meta-analysis - MedRxiv - "We included 15 randomised trials investigating the effect of masks (14 trials) in healthcare workers and the general population and of quarantine (1 trial). We found no trials testing eye protection. Compared to no masks there was no reduction of influenza-like illness (ILI) cases or influenza for masks in the general population, nor in healthcare workers. There was no difference between surgical masks and N95 respirators: for ILI, or for influenza.
The use of masks and respirators to prevent transmission of influenza: a systematic review of the scientific evidence - bin‐Reza et al. (2012) - "In conclusion, there is a limited evidence base to support the use of masks and/or respirators in healthcare or community settings."
Use of surgical face masks to reduce the incidence of the common cold among health care workers in Japan: a randomized controlled trial - PubMed - "Face mask use in health care workers has not been demonstrated to provide benefit in terms of cold symptoms or getting colds."
Face masks to prevent transmission of influenza virus: a systematic review - Cambridge University Press - "There is little evidence to support the effectiveness of face masks to reduce the risk of infection."
Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers, A Randomized Controlled Trial - Annals of Internal Medicine - "Our results suggest that the recommendation to wear a surgical mask when outside the home among others did not reduce, at conventional levels of statistical significance, the incidence of SARS-CoV-2 infection in mask wearers in a setting where social distancing and other public health measures were in effect, mask recommendations were not among those measures, and community use of masks was uncommon."
Face Coverings, Aerosol Dispersion and Mitigation of Virus Transmission Risk - arxiv.org - "Surgical and handmade masks, and face shields, generate significant backward leakage jets that have the potential to disperse virus-laden fluid particles by several metres. The handmade mask and the face shield opened at the bottom, showed an intense downward jet. The different nature of the masks and shields makes the direction of these jets difficult to be predicted..."
A cluster randomised trial of cloth masks compared with medical masks in healthcare workers - BMJ - "This study is the first RCT of cloth masks, and the results caution against the use of cloth masks. This is an important finding to inform occupational health and safety. Moisture retention, reuse of cloth masks and poor filtration may result in increased risk of infection."
Postoperative wound infections and surgical face masks: A controlled study - World Journal of Surgery - "These results indicate that the use of face masks might be reconsidered. Masks may be used to protect the operating team from drops of infected blood and from airborne infections, but have not been proven to protect the patient operated by a healthy operating team."
Is a mask necessary in the operating theatre? - Royal College of Surgeons - "No masks were worn in one operating theatre for 6 months. There was no increase in the incidence of wound infection."
Effectiveness of Surgical and Cotton Masks in Blocking SARS–CoV-2: A Controlled Comparison in 4 Patients - Annals of Internal Medicine (Retracted but still visible) - "Neither surgical nor cotton masks effectively filtered SARS–CoV-2 during coughs by infected patients."
Surgical Attire and the Operating Room: Role in Infection Prevention - The Journal of Bone and Joint Surgery - "Although there is some evidence that scrubs, masks, and head coverings reduce bacterial counts in the operating room, there is no evidence that these measures reduce the prevalence of surgical site infection."
Dubious effect of surgical masks during surgery - Europe PMC - "None of the four studies found a difference in the number of post-operative infections whether you used a surgical mask or not."
Disposable surgical face masks for preventing surgical wound infection in clean surgery - Cochrane Library - "Three trials were included, involving a total of 2113 participants. There was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials."
Disposable surgical face masks for preventing surgical wound infection in clean surgery (Update 2016) - Cochrane Library - "We included three trials, involving a total of 2106 participants. There was no statistically significant difference in infection rates between the masked and unmasked group in any of the trials. We identified no new trials for this latest update."
Use of face masks by non‐scrubbed operating room staff: a randomized controlled trial - ANZ Journal of Surgery - "site infections were recorded; 46/401 (11.5%) in the Masked group and 37/410 (9.0%) in the No Mask group" - "Surgical site infection rates did not increase when non‐scrubbed operating room personnel did not wear a face mask."
Does evidence based medicine support the effectiveness of surgical facemasks in preventing postoperative wound infections in elective surgery? - Journal of Ayub Medical College - "No significance difference in the incidence of postoperative wound infection was observed
between masks group and groups operated with no masks. There was no increase in infection rate in 1980 when masks were discarded. In fact there was significant decrease in infection rate"
Bag Exchange in Continuous Ambulatory Peritoneal Dialysis Without Use of a Face Mask: Experience of Five Years - Renal Unit, Hospital São Lucas, Porto Alegre, Brazil. - "Peritonitis rates reported during our observation period are compatible with those seen in other centers and support the hypothesis that routine use of a face mask during CAPD bag exchange may be unnecessary."
Patient surgical masks during regional anesthesia. Hygenic necessity or dispensable ritual? - Europe PMC - "Surgical face masks worn by patients during regional anaesthesia, did not reduce the concentration of airborne bacteria over the operation field in our study. Thus they are dispensable."
Do Anaesthetists Need to Wear Surgical Masks in the Operating Theatre? A Literature Review with Evidence Based Recommendations - Anaesth Intensive Care 2001 - "The evidence for discontinuing the use of surgical face masks would appear to be stronger than the evidence available to support their continued use... There is little evidence to suggest that the wearing of surgical face masks by staff in the operating theatre decreases postoperative wound infections. Published evidence indicates that postoperative wound infection rates are not significantly different in unmasked versus masked theatre staff. However, there is
evidence indicating a significant reduction in postoperative wound infection rates when theatre staff are unmasked."
Wearing of caps and masks not necessary during cardiac catheterization - Catheterization and Cardiovascular Interventions - "No infections were found in any patient, regardless of whether a cap or mask was used. Thus, we found no evidence that caps or masks need to be worn during percutaneous cardiac catheterization."
Is use of surgical caps and masks obsolete during percutaneous heart catheterization? - Europe PMC - "The routine use of caps and masks does not seem to have that much beneficial impact on the occurrence of procedure-related inflammations or infections in the cardiac catheterisation laboratory."
Respirators and Surgical Masks: A Comparison - 3M Technical Bulletin - "Surgical/procedure masks cannot provide certified respiratory protection unless they are also designed, tested, and government-certified as a respirator. If a wearer wants to reduce inhalation of smaller, inhalable particles (those smaller than 100 microns), they need to obtain and properly use a government-certified respirator, such as a NIOSH-approved N95 filtering facepiece particulate respirator."
Surgical Mask to Prevent Influenza Transmission in Households: A Cluster Randomized Trial - PLoS - "Influenza-like illness was reported in 24/148 (16.2%) of the contacts in the intervention arm and in 25/158 (15.8%) of the contacts in the control arm... We observed a good adherence to the intervention. In various sensitivity analyses, we did not identify any trend in the results suggesting effectiveness of facemasks."
Facemask against viral respiratory infections among Hajj pilgrims: A challenging cluster-randomized trial - PLoS - "By intention-to-treat analysis, facemask use did not seem to be effective against laboratory-confirmed viral respiratory infections nor against clinical respiratory infection. Similarly, in a per-protocol analysis, facemask use did not seem to be effective against laboratory-confirmed viral respiratory infections nor against clinical respiratory infection"
Articles:
Masking lack of evidence with politics - Centre for Evidence-Based Medicine - Tom Jefferson, Carl Heneghan
Do face masks work in combating Covid? Not in my old people’s nursing home they don’t... - Dr Malcolm Kendrick
Why Face Masks Don’t Work: A Revealing Review - Oral Health Group (web.archive.org)
Sweden’s disease expert says just wearing face masks could be ‘very dangerous’ - "Sweden’s top infectious disease expert has resisted recommending face masks for the general population — arguing it’s “very dangerous” if people believe the coverings alone will stop the spread of the coronavirus..." "....Tegnell has argued that evidence about the effectiveness of face mask use was “astonishingly weak.”"
Resources:
Masks Are Neither Effective Nor Safe: A Summary Of The Science - Primary Doctor Medical Journal
Mask Facts - Association of American Physicians and Surgeons
Open Letter to UK Government ministers regarding the current face covering mandates - UK Medical Freedom Alliance
MASK WHISTLEBLOWERS TELL ALL - Video - "Government trained OSHA mask experts Tammy Clark & Kristen Meghan join Del Bigtree in-studio to break down vital info on masks, PPE, and their role in #Covid19 prevention."
A visual demonstration of the efficacy of masks: Click on picture below to go to video.
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