What Mask to Wear during Pneumonia outbreak? Surgical Mask or N95 Mask?

The outbreak of an unknown pneumonia in Wuhan, China and suspected cases in Hong Kong have caused great concern among the Hong Kong public.

N95 masks, used by medical personnel during the SARS outbreak, is experiencing panic buying. What masks should an average citizen actually wear? Surgical masks or N95 masks?

Professor David SC HUI of the Department of Medicine and Therapeutics of CUHK cited a report last year by the Journal of the American Medical Association (JAMA), analysing the probability of medical personnel wearing N95 masks or surgical masks contracting influenza. Results had shown that 8.2% of medical personnel wearing N95 masks contracted influenza, while 7.2% of those wearing surgical masks contracted Influenza, indicating there is no significant difference in the effectiveness between the two.

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Surgical Masks
Surgical masks are designed to prevent droplet transmission of diseases, and are suitable for unventilated environments like clinics and surgical theatres. However, it could not block particles with the radii smaller than 5μm, nor could it block any particulates or gases (including tear gas).

According to information from the Consumer Council, the three layers present in a typical surgical masks has three individual functions: the innermost layer retains moisture; the middle layer filters particles in the air; and the outermost layer resists water. However, surgical masks are disposable medical items with a maximum use time of 6 - 8 hours. The mask must also be replaced if it is broken, wet, or dirty.

Characteristics:
．Block disease-transmitting droplets
． Retain moisture, filter particles, and resist water
． Could not block droplets with radii smaller than 5μm

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N95 Masks
N95 masks are masks that abide to the National Institute for Occupational Safety and Health's standards, which filters at least 95% of airborne particles but is not resistant to oil aerosols.

However, N95 masks are designed to fit perfectly onto the face, which results in the user breathing in their own exhaled carbon dioxide. Thus long-time usage could cause headaches due to dilation of cerebral blood vessels. It is recommended that users should replace the mask after eight hours of usage.

Characteristics:
．Filters at least 95% of airborne particles
．Not resistant to oil aerosols
．Long usage causes headaches

Exhalation valves are also present in some N95 masks, with the valve designed to be a single valve which reduces exhalation resistance, making it easier to breathe (exhale). However, the exhalation valve does not reduce inhalation resistance. Since air exhaled from the exhalation valve does not undergo filtration, wearers could still spread pathogens as though they have not wore a mask, thus masks with exhalation valves are not suitable for patients.

Source: Health Concept 健康概念; Consumer Council; Centers for Disease Control of Republic of China (Taiwan); "N95 Respirators vs Medical Masks for Preventing Influenza Among Health Care Personnel, A Randomized Clinical Trial"

#4Jan #Pneumonia #Plague

Emergency Notice:
https://t.me/guardiansofhongkong/14769

8 mystery pneumonia cases found in 5 days; Microbiologist warned for a surge during Chinese New Year

Government announced 3 new suspected mystery pneumonia case from Wuhan in China on Jan 4, making a total of 8 cases in the past 5 days, although none was considered severe.

Secretary for Food and Health Bureau, Sophia Chan, said the government has been vigilant and a series of measures would be put in place, including cutting down the visiting time in public hospital to reduce the flow of people. Staff might be sent to Wuhan to understand the situation, and amendments would be proposed to the Prevention and Control of Disease Ordinance, which required reporting of all concerning suspected cases.

Earlier today, the head of the University of Hong Kong's Centre for Infection, Ho Pak-leung, urged the Government to deploy all possible monitoring system at the city's borders, including the high-speed rail terminus for the new viral pneumonia from mainland.

Although Wuhan officials said that no evidence of human to human transmission had been found, Ho remained firm on his view that the virus could possibly pass from person to person. Ho hoped the mainlaid authority could release more information to help experts analyse the illness.

Ho also said, "so many infections in such a short period of time in Wuhan is worrying". The microbiologist, at the same time, warned for a surge in cases during Chinese New Year.

Emergency Notice:
https://t.me/guardiansofhongkong/14769

What Mask to Wear during Pneumonia outbreak?
https://t.me/guardiansofhongkong/14847

In #Singapore, Chinese girl with pneumonia warded, isolated after travel to Wuhan, China
https://t.me/guardiansofhongkong/14851

Source RTHK #4Jan #Pneumonia #Plague