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Do masks protect?
• Neil Orr’s study, 1981 in the Annals of the Royal College of Surgeons of England. Dr. Orr was a surgeon in the Severalls Surgical Unit in Colchester. And for six months, from March through August 1980, the surgeons and staff in that unit decided to see what would happen if they did not wear masks during surgeries. They wore no masks for six months, and compared the rate of surgical wound infections from March through August 1980 with the rate of wound infections from March through August of the previous four years. And they discovered, to their amazement, that when nobody wore masks during surgeries, the rate of wound infections was less than half what it was when everyone wore masks. Their conclusion: “It would appear that minimum contamination can best be achieved by not wearing a mask at all” and that wearing a mask during surgery “is a standard procedure that could be abandoned.”
• Ritter et al., 1975, “the wearing of a surgical face mask had no effect upon the overall operating room environmental contamination.”
• Ha’eri and Wiley, 1980, applied human albumin microspheres to the interior of surgical masks in 20 operations. At the end of each operation, wound washings were examined under the microscope. “Particle contamination of the wound was demonstrated in all experiments.”
• Laslett and Sabin, 1989, “No infections were found in any patient, regardless of whether a cap or mask was used,” they wrote. Sjøl and Kelbaek came to the same conclusion in 2002.
• In Tunevall’s 1991 a general surgical team wore no masks in half of their surgeries for two years. After 1,537 operations performed with masks, the wound infection rate was 4.7%, while after 1,551 operations performed without masks, the wound infection rate was only 3.5%.
• A review by Skinner and Sutton 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.”
• Lahme et al., 2001, “surgical face masks worn by patients during regional anaesthesia, did not reduce the concentration of airborne bacteria"
• Figueiredo et al., 2001, in five years of doing peritoneal dialysis without masks, rates of peritonitis in their unit were no different than rates in hospitals where masks were worn.
• Bahli 2009 “no significant difference in the incidence of postoperative wound infection was observed between masks groups and groups operated with no masks.”
• Surgeons at the Karolinska Institute in Sweden, “Our decision to no longer require routine surgical masks for personnel not scrubbed for surgery is a departure from common practice. But the evidence to support this practice does not exist,” wrote Dr. Eva Sellden.
• Webster et al., 2010, on obstetric, gynecological, general, orthopaedic, breast and urological surgeries performed on 827 patients. All non-scrubbed staff wore masks in half the surgeries, and none of the non-scrubbed staff wore masks in half the surgeries. Infections occurred in 11.5% of the Mask group, and in only 9.0% of the No Mask group.
• Lipp and Edwards 2014 “no statistically significant difference in infection rates between the masked and unmasked group in any of the trials.” Vincent and Edwards updated this review in 2016 and the conclusion was the same.
• Carøe, 2014: 6,006 patients, wrote that “none of the four studies found a difference in the number of post-operative infections whether you used a surgical mask or not.”
• Salassa and Swiontkowski, 2014, “there is no evidence that these measures [masks] reduce the prevalence of surgical site infection.”
• Da Zhou et al., 2015, “there is a lack of substantial evidence to support claims that facemasks protect either patient or surgeon from infectious contamination.”
Arthur Firstenberg, August 11 2020
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