From an e-mail I’ve received, interesting studies on masks:
“As a person who went to medical school, I was shocked when I read Neil Orr’s study, published in 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.””
Here is the original study published on the NIH website so it’s official:
The e-mail the lists these studies:
Ritter et al., in 1975, found that “the wearing of a surgical face mask had no effect upon the overall operating room environmental contamination.”
Ha’eri and Wiley, in 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, in 1989, found that caps and masks were not necessary during cardiac catheterization. “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 study, 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 in 2001 concluded that “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., in 2001, wrote that “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.”
Figueiredo et al., in 2001, reported that 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 did a systematic literature review in 2009 and found that “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, recognizing the lack of evidence supporting the use of masks, ceased requiring them in 2010 for anesthesiologists and other non-scrubbed personnel in the operating room. “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., in 2010, reported 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. Surgical site infections occurred in 11.5% of the Mask group, and in only 9.0% of the No Mask group.
Lipp and Edwards reviewed the surgical literature in 2014 and found “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, in a 2014 review based on four studies and 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, in 2014, investigated the necessity of scrubs, masks and head coverings in the operating room and concluded that “there is no evidence that these measures reduce the prevalence of surgical site infection.”
Da Zhou et al., reviewing the literature in 2015, concluded that “there is a lack of sub
No surprise to anyone in sceptics and is it?