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article imageHand washing not as effective as thought against the flu

By Stephanie Dearing     Oct 2, 2009 in Health
There is a commonly held assumption that hand washing, also known as 'proper hygiene,' prevents the spread of respiratory illnesses such as influenza. New research on the topic shows that hand washing is not an effective tool.
The research was commissioned by Health Canada and conducted by the Council of Canadian Academies reports the Canadian Medical Association in its journal. However, when it comes to preventing the spread of the flu, face masks such as the N95 respirator, are actually very effective at reducing the transmission of the disease. Last year when the swine flu first broke out, many medical spokespersons said that wearing face masks would not slow the spread of the flu. Even this past September, the Center for Disease Control in the United States said "In community and home settings, the use of facemasks and respirators generally are not recommended. However, for certain circumstances as described in Table 1, a facemask or respirator may be considered, specifically for persons at increased risk of severe illness from influenza."
The Canadian study report is called Influenza Transmission and the Role of Personal Protective Respiratory Equipment: An Assessment of the Evidence. Concluded in 2007, the report was only recently released after undergoing an extensive peer review. The report states that there are two main ways the flu is spread by someone who is sick with the virus -- sneezing, coughing, speaking and breathing. The other main way is direct contact between people.
A detailed study of the droplets released by an infected person was undertaken by a panel of 12 scientists, led by Dr. Donald Low, the Microbiologist-in-Chief at McMaster University. Droplets differ in their size as to how far they travel and also in whether or not they might be inhaled by someone else who is nearby. "Inhalable" droplets, the scientists found, can stay in the air for as little as seconds and as long as days. The report concluded that it was reasonable to assume that there could be some transmission of the influenza virus from contact with a contaminated surface, but that this route has not been demonstrated as being the way the flu is spread.
Dr. Donald Low told the Canadian Medical Association Journal "Every time you talk, laugh, cough, sneeze, you’re generating particles that are coming out of your mouth that are various sizes. Large “ballistic” particles over 100 microns fall to the ground. But smaller particles ranging from 0.1 to 100 microns stay in the air from seconds to days, depending on humidity, airflow and ultraviolet light. These particles can be inhaled deeply into the respiratory tract, with smaller ones capable of reaching the tracheobronchial and alveolar tissues. In practice, studies show the greatest risk is within one metre [of distance between people. Whether someone is infectious will vary [with] the amount of virus. There’s a huge dilutional factor right away as soon as you get away from the person infected.”
The scientists recommend that health care practitioners practice a "hierarchy of control" to limit the spread of the flu, meaning to have more than one way to reduce possible transmission. The three recommended methods are supposed to be used at the same time and consist of what the scientists term Engineering, Administrative and Personal Protection. Engineering encompasses air ventilation, temperature and humidity in a building. Administrative is hand hygiene, respiratory hygiene and separation of people with influenza from others. Personal protective equipment is exactly what the reader might think -- goggles, face masks, gloves, surgical gowns, and respirators. The N95 respirator, along with other face masks were assessed for their effectiveness in preventing airborne transmission of the flu. The N95 was found to be the most effective, if the mask is worn properly.
The report recommended that the N95 or a similar mask be adopted by Health Canada as a "final layer of protection for health care workers." Health Canada reportedly will not be adopting the use of the N95. Health Canada is still promoting hand washing as the number one way to prevent the spread of the H1N1 virus.
According to the U.S. Food and Drug Administration, "An N95 respirator is a respiratory protective device designed to achieve a very close facial fit and very efficient filtration of airborne particles. In addition to blocking splashes, sprays and large droplets, the respirator is also designed to prevent the wearer from breathing in very small particles that may be in the air."
The N95 mask costs about $30.00 Canadian.
More about Hand washing, H1n1, Swine flu, Flu transmission, N95 repirator
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