Guest guest Posted May 1, 2003 Report Share Posted May 1, 2003 > > April 29, 2003 -- The images of mask-covered men, women, and children > have > been linked with SARS (severe acute respiratory syndrome) since the > outbreak > began. Sales of the paper masks have soared in areas hardest hit by SARS > as > people try to protect themselves from an unknown enemy. But how much > protection can a simple mask offer from SARS? > > Despite their popularity in Asia, experts say standard surgical masks -- > the > inexpensive square masks that tie behind your head -- are probably more > effective in preventing people with SARS from spreading the disease > than > protecting healthy people from becoming infected. > > CDC director Julie Gerberding, MD, says surgical masks are useful in > filtering out relatively large particles of moist materials that you > cough > up or sneeze, which reduces the likelihood of passing SARS to another > person. > > " That's the reason why we recommend that those masks be used for > patients > with SARS because it contains their secretions and prevents them from > being > disseminated in the environment, " says Gerberding. > > Infectious disease expert Jon Temte, MD, PhD, of the University of > Wisconsin > says the pictures of people in Beijing and Hong Kong wearing surgical > masks > remind him of the influenza pandemic of 1918. > > " I remember looking at old photos from the 1918 influenza pandemic and > seeing people wearing masks everywhere, " says Temte. " But that was > never > shown to be effective for preventing the spread of influenza. " > > Temte says it's really to early to know whether masks are an effective > way > to protect against SARS. Researchers simply don't know enough about the > virus and how it spreads. > > " On the flip side, there is probably not a whole lot of harm in it, " > Temte > tells WebMD. " Any sort of barrier will reduce likelihood of droplet > transmission. " > > Health officials at the World Health Organization and CDC believe SARS > is > spread primarily by close contact with droplets from an infected person. > > > " So if we're looking at a viral transfer on the basis of coughing up > small > droplets, when that droplet travels the distance between the person and > the > unlucky recipient and lands on fertile ground, you have transmission, " > says > Temte. > > Wearing a mask may protect people from inhaling these droplets and > becoming > infected, but the masks usually don't fit snugly and can allow droplets > to > enter the mouth or nose from the edges of the mask. > > Although droplet transmission through close, personal contact with an > infected individual is believed to be the primary mode of transmission > of > SARS, health officials have not ruled out the possibility that tiny > particles of the SARS coronavirus may also spread the disease through > the > air. If such transmission is possible, some of these tiny virus > particles > may pass through a simple surgical mask or enter through an air gap. > > Surgical masks also provide no protection for the eyes, and some types > of > virus particles can enter the body through the eyes as well as the mouth > and > nose. > > In addition, some types of coronaviruses are known to survive on objects > for > several hours, which means it's possible that person with SARS person > could > sneeze and infect an object like a door knob that is later touched by > someone who then rubs their eyes, nose, or mouth and becomes infected > in > that manner. > > For protecting people from SARS infection, the CDC recommends that > healthcare providers who care for SARS patients wear a much more > efficient > mask known as an N95 respirator. This type of mask is certified by the > National Institute of Occupational Safety and Health (NIOSH) as being > effective at filtering out at least 95% of airborne particles of a > particular size. > > There are also N99 and N100 masks that are even more efficient, but N95 > masks are considered the standard for preventing infection from most > known > viruses. > > But for these masks to work, they must be properly fitted to make sure > there > are no gaps between the mask and the skin. The mask is made of a > thicker > material than regular surgical masks and, when properly fitted, does > not > allow air to flow outside the mask. > > Gerberding says N95 masks are only recommended for healthcare workers > caring > for SARS patients because they are at greatest risk of becoming > infected. In > fact, the majority of initial SARS cases were among doctors, nurses, > and > medical students who cared for the first round of SARS patients and did > not > wear such protection. Since infection control measures such as wearing > N95 > masks were implemented, the rate of SARS spread to healthcare workers > has > been drastically reduced. > > " We don't recommend N95 masks for the general public. We don't recommend > N95 > masks for patients, " says Gerberding. " We are recommending surgical > masks > for patients if they're well enough to wear one, and we're using those > N95 > masks in the healthcare environment in hospitals where we've got sick > patients most likely to be aerosolizing relatively high concentrations > of > infectious material. " > > To reduce the risk of SARS transmission in the general public, the CDC > recommends following good hygiene practices, such as frequent hand > washing > and use of alcohol-based rubs, and avoiding areas where SARS is known > to > have been spread. > > _____ > > SOURCES: CDC telebriefing, April 22. World Health Organization. Jon > Temte, > MD, PhD, associate professor at the University of Wisconsin in the > department of family medicine. > > Quote Link to comment Share on other sites More sharing options...
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