Masks at frontline of defence

Prices quoted for masks vary widely. Picture / Richard Robinson

Face masks are expected to form a key defence against the spread of a bird flu pandemic, although uncertainties remain about their use.

* Human influenza is spread from person to person mainly by large droplets, containing virus, sneezed and coughed out by an infected person.

* Washing hands with soap, alcohol-based or antiseptic cleanser - and drying them - are considered the most important ways of reducing the risk of spreading any infectious organisms between people.

* Various disposable masks are available from pharmacies, hardware stores and medical goods suppliers.

* The World Health Organisation (WHO) recommends use of N95 respiratory masks or well-fitted standard surgical masks.

* N95 masks filter out smaller particles than surgical masks do and can be used for longer, but are harder to breathe through. N95 masks with a exhalation vent are easier to breathe through than those without, but are considered unsuitable for people who have flu.

* One supplier sells surgical masks for just over 20c each ($10.13 for a pack of 50). N95 prices quoted to the Herald range from $1.88 each ($37.75 for a box of 20) at a pharmacy to $5.48 each ($10.95 for a pack of two) at a hardware store.

* The Health Ministry says that in a flu pandemic people with flu symptoms, such as fever, headache and coughing, should consider using a disposable surgical mask to avoid exposing others to flu virus.

* Masks must be appropriately disposed of once wet and hands then washed and dried.

* The ministry recommends increasing levels of protection depending on the risks: from disposable surgical masks for "first responders" like ambulance officers, health workers or support people in the community, to higher-level masks, goggles, gloves and gown for hospital staff performing invasive procedures on flu patients, such as putting them on a ventilator.

* Senior public health adviser Dr Andrea Forde says the role of masks will not be fully known until a pandemic occurs, when the virus' characteristics will be clearer. Sick people will be urged to wear a mask in public but it is unknown if they should do so at home. People with breathing difficulty cannot be left wearing a mask.

* The WHO says mask-wearing by the general population is not expected to have much impact on flu transmission, "but should be permitted, as this is likely to occur spontaneously".

* Cough "etiquette". During a pandemic people should keep a distance of 1m from others, cover their mouth when coughing or sneezing, use disposable tissues over their mouth and nose, put used tissues in a rubbish bin and wash and dry their hands immediately.

* Large public gatherings should be avoided and any social contact with infected people should be avoided if possible.

* Windows should be opened for ventilation or a good air-conditioning system used.

* Employers are urged to put up glass or perspex barriers to protect the likes of supermarket check-out staff and bus drivers.