Credit @WHO June 13th, 2013
# 7391
Yesterday, in WHO: MERS, Masks, And The Media, we looked at a story published by the International Business Times that (incorrectly) stated that the World Health Organization recommended that pilgrims going to Saudi Arabia for Umrah or this year’s Hajj wear masks in public.
This story, as you might imagine, immediately went viral. Despite attempts by WHO to set the record straight, It was re-tweeted vigorously on Twitter, and picked up by other wire services.
Overnight, WHO’s social media arm again tried to correct the story, referring to a 2009 statement (excerpts below) on mask wearing during the H1N1 pandemic.
For the record, WHO defines `masks’ as:
The term “mask” is used here to include home-made or improvised masks, dust masks and surgical masks (sometimes called “medical masks”). Masks have several designs. They are often single use and labelled as either surgical, dental, medical procedure, isolation, dust or laser masks. Masks frequently used outside health-care settings may also be made out of cloth, or paper or similar material. Masks, names and standards differ among countries.
Advice on the use of masks in the community setting in Influenza A (H1N1) outbreaks Interim guidance
3 May 2009
This document provides interim guidance on the use of masks in communities that have reported community-level outbreaks caused by the new Influenza A(H1N1) virus. It will be revised as more data become available.
<SNIP>
In health-care settings, studies evaluating measures to reduce the spread of respiratory viruses suggest that the use of masks could reduce the transmission of influenza. Advice on the use of masks in health-care settings is accompanied by information on additional measures that may have impact on its effectiveness, such as training on correct use, regular supplies and proper disposal facilities. In the community, however, the benefits of wearing masks has not been established, especially in open areas, as opposed to enclosed spaces while in close contact with a person with influenza-like symptoms.
Nonetheless, many individuals may wish to wear masks in the home or community setting, particularly if they are in close contact with a person with influenza-like symptoms, for example while providing care to family members.
Furthermore, using a mask can enable an individual with influenza-like symptoms to cover their mouth and nose to help contain respiratory droplets, a measure that is part of cough etiquette.
Using a mask incorrectly however, may actually increase the risk of transmission, rather than reduce it. If masks are to be used, this measure should be combined with other general measures to help prevent the human-to-human transmission of influenza, training on the correct use of masks and consideration of cultural and personal values.
<SNIP>
If masks are worn, proper use and disposal is essential to ensure they are potentially
effective and to avoid any increase in risk of transmission associated with the incorrect
use of masks. The following information on correct use of masks derives from the practices in
health-care settings
• place mask carefully to cover mouth and nose and tie securely to minimise any gaps between the face and the mask
• while in use, avoid touching the mask
− whenever you touch a used mask, for example when removing or washing, clean hands by washing with soap and water or using an alcohol-based handrub
• replace masks with a new clean, dry mask as soon as they become damp/humid
• do not re-use single-use masks
− discard single-use masks after each use and dispose of them immediately upon removing.
Although some alternative barriers to standard medical masks are frequently used (e.g. cloth
mask, scarf, paper masks, rags tied over the nose and mouth), there is insufficient information
available on their effectiveness.
If such alternative barriers are used, they should only be used once or, in the case of cloth masks, should be cleaned thoroughly between each use (i.e. wash with normal household detergent at normal temperature). They should be removed immediately after caring for the ill. Hands should be washed immediately after removal of the mask.
While not recommending the public use of masks, WHO doesn’t come out strongly against them, either. And should the threat from MERS change, WHO could very well adjust their recommendations down the line.
The best use of surgical or procedure masks is undoubtedly having the person who is sick and symptomatic wear one.
Those contemplating using masks for personal protection should be aware that there’s considerable debate over how effective surgical or procedure masks are at preventing respiratory virus transmission.
The data is mixed, and we’ve looked at a number of studies, including:
Why Size Matters
Study: Aerosolized Transmission Of Influenza
NPI’s and Influenza
NEJM Perspective: Respiratory Protection For HCWs
And while we don’t know much about how MERS-CoV is transmitted, we do know that some respiratory viruses can enter a host through the eyes ( see PPEs & Transocular Influenza Transmission), significantly limiting the effectiveness of just wearing a mask.
There is also a concern that masks could give the wearer a false sense of security, and that might lead to more risky behavior, or a failure to maintain hand hygiene.
Although supplies are not a problem now - during a severe pandemic – the world would be faced with a severe shortage of masks.
At one time the HHS estimated the United States alone would need 30 billion masks (27 billion surgical, 5 Billion N95) to deal with a major pandemic (see Time Magazine A New Pandemic Fear: A Shortage of Surgical Masks).
All of which – when taken together – makes it difficult for the WHO, or any other public health agency, to recommend the use of masks in public at this time.
Personally, while I have a modest stash of surgical & N95 masks in my emergency kit – during a serious local outbreak of a respiratory virus - my preference would be to try to avoid situations where I felt a mask would be advisable.
But if that proved impossible or impractical, I’d go with some form of respiratory protection as part of a larger strategy to avoid infection; one that emphasized avoiding close contact to those visibly ill, enhanced hand hygiene, not touching my face, and staying away from crowds.
