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 With the northern hemisphere flu season currently very active, it is a reminder that the Australian flu season is only a matter of months away. The Influenza Specialist Group will again be reminding people that the best way to prevent the disease is through vaccination. Vaccination also helps to stop the spread of influenza. The role of facemasks in protection from influenza is often raised as a point of discussion, and this article might help shine some light on current knowledge.
Influenza is thought to be largely transmitted from person to person primarily via virus-laden large droplets (particles >5 μm in diameter) that are generated when infected persons cough or sneeze; these large droplets can then be directly deposited onto the mucosal surfaces of the upper respiratory tract of susceptible persons who are near (i.e., within 1 meter) the droplet source. There is some evidence that smaller droplets (aerosols) which persist in the air for longer periods and travel further may also be involved in transmission which can also occur through direct and indirect contact with infectious respiratory secretions deposited on surfaces (door handles etc).
Types of face masks
Masks that have been used in studies include:
Surgical Mask
A loosely fitting mask designed to reduce transmission of fluid droplets that may spread infection, but may also be used as barriers against disease transmission. They are not designed to fully protect the wearer from entry of all types of infectious particles and this may occur via leakage around or even through the mask.
Disposable P2/N95 Respirator
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P2: A particulate filter, personal respiratory protection device which, when tested against the Australian standard for Respiratory Protective Devices (AS/NZS 1716:2003), filter out at least 95% of particles of 0.3 micrometers diameter.
These are most commonly used in high risk environments and to be fully effective the wearer should preferbly be trained in fitting and using the mask.
Will my wearing a mask protect me from the flu?
There have now been a number of studies conducted looking at the use of surgical masks and P2/N95 respirators in the healthcare setting. An Australian study found that adherence to mask use significantly reduced the risk for ILI-associated infection [1]. For example, in families with a sick child, parents who wore a mask are four times less likely to get sick with flu and other respiratory viruses than parents who did not wear a mask.
Will my wearing a mask protect others from the flu?
There have not been any studies looking at this question. If you are sick, however, it would be plausible that wearing a mask would reduce the risk of infecting other people.
How are facemasks used effectively?
They must be worn at all times when exposed to sick people, and must cover the nose and mouth properly. They need to be changed regularly - three or more times a day on average. They must also be replaced if they become damp. Hand hygiene is also very important when donning or removing the facemask.
Should they be used as standard practice during the flu season?
If there is a pandemic or an epidemic of severe flu in Australia, masks are one of the many protective strategies we have at our disposal. They would be particularly beneficial in the period when a matched vaccine is not yet available. Other non-pharmaceutical measures such as good hand washing practices, avoiding going to work if sick and keeping children home from school if they are sick should also be standard.
What are the features I should look for when purchasing a facemask?
Surgical masks or the P2/N95 respirators are suitable. Other types of masks such as dust masks are not designed for infection control and are not recommended.
Where do I go to purchase a mask?
Most pharmacies would stock surgical masks
[1] MacIntyre C, Cauchemez S, Dwyer DE, Seale H, Cheung P, Browne G, et al. Face mask use and control of respiratory virus transmission in households. Emerg Infect Dis 2009;15:233-41.
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Newsletter 
The ISG's annual scientific meeting will be taking place in the first week of February. This is an event that takes place each year, and enables a broad range of discussion on a variety of influenza and related issues. Attendees and presenters include members of the scientific and medical community, government health officials, pharmaceutical industry representatives, academics, and delegates from other health related NGO's. Attendance at the conference is however by invitation only, and is one of the key influenza related meetings held in Australia.
The Australian Immunisation Handbook developed by the Australian Technical Advisory Group on Immunisation (ATAGI) and endorsed by the National Health and Medical Research Council (NHMRC), recommends annual influenza vaccination 'for any person >6 months of age who wishes to reduce the likelihood of becoming ill with influenza'.
The influenza risk assessment tool has been designed by the ISG to assist the community in identifying their risk of contracting influenza and of suffering serious consequences from influenza infection. It is intended to be used as a guide only and is not an authoritative statement. Speak with your doctor about your symptoms, for medical opinion or advice and take this checklist along with you to your appointment.