Dr Lucia Gannon
Scientists and the general public seem to be undecided about the role of face masks in the prevention of coronavirus infection.
The World Health Organisation (WHO) says that there is not enough evidence to suggest that wearing masks is of any benefit.
The European Center for Disease Control (ECDC), disagrees and states that masks may have a role in public transport and when going to supermarkets.
The reason that there is disagreement it that the question does not have a simple answer.
Not all masks are the same. There are three types that people talk about.
Surgical masks are the most common. They are not sealed around the face and are for single use only. The function of these masks is, not to protect the wearer, but to limit the spread of infection to others. Surgeons and those attending to patients on oncology wards wear surgical masks. However, they can be bought in pharmacies and are frequently worn by members of the public. These masks prevent the spread of the large droplets that we emit when we cough, sneeze or speak. These droplets carry the virus and travel up to one meter before landing on a surface. By staying at least two meters away from others we are already protecting them from this droplet spread and it is unlikely that wearing a mask offers any additional benefit.
The second type of mask is called a respirator mask. These are sealed around the nose and mouth. Respirator masks prevent the spread of large droplets to others, and also prevents the wearer from inhaling small aerosol droplets of virus. These masks are worn by carers of confirmed cases of COVID-19, in order to protect the carer. They are uncomfortable to wear and can frequently lead to abrasion burns on the face.
The third type of mask is the cloth mask, available in chemists, online or can be homemade. Members of the public frequently wear cloth masks. Cloth masks can be re-used if washed correctly. Like surgical masks, they may reduce the spread of the virus to others by catching the large droplets emitted by coughing, sneezing and speaking. They do not protect the wearer from inhaling small virus particles. Some fabrics may be more effective than others, but there are no scientific studies to guide the use of cloth masks in a pandemic.
At the moment, the expert advice in Ireland is that a mask is unlikely to be of benefit in limiting spread of the virus unless you are sick, and if you are sick, you should stay at home. Therefore, there is no additional benefit to wearing masks in public. But this advice may change. What will not change, however, is that we must continue to wash our hands, keep our hands away from our face, cough into a tissue or our elbow, maintain social distancing and stay home if we are ill.
Some countries such as Austria and the Czech Republic have made mask-wearing in public a requirement. These countries believe that if there is even the slightest chance that wearing a mask will reduce the spread of infection, then it is worth doing it. Because coronavirus is such a severe illness, they believe that we should be doing everything in our power to limit the spread.
People have been wearing masks in Asian countries since the SARS outbreak in 2003. Mask-wearing has now become part of their culture. South Korea appears to be reducing the spread of disease since they started to wear masks in public. This reduction may be related to the masks, or to some other coincidental change in behaviour, that has nothing to do with wearing masks.
There are a few reasons why the experts are cautious about recommending mask-wearing in public in Ireland. There is a global shortage of surgical masks. It is important that they are preserved for healthcare workers who work in close contact with vulnerable people.
Masks need to be used properly. The HSE website has a video which shows people how to put on and take off a mask. If you wear a mask while shopping or on public transport, you should leave it on until you get home and then remove it without touching the front of the mask. Wash your hands before and after taking it off. If it is a cloth mask, it should be put in a wet bag and washed in a washing machine at sixty degrees. It is best to put it in a half-load to ensure that it is cleaned thoroughly.
All masks are uncomfortable and can result in you touching your face a lot more than you would if you were not wearing it. Every time you adjust your mask, you put yourself at risk of contracting the virus. Therefore, you must weigh the benefit of protecting others from infection against the risk of contaminating yourself.
Cloth and disposable surgical masks will not prevent you from inhaling the virus. Only the sealed respirator ones will do this.
If you have an infection, cloth and surgical masks will significantly reduce the chances of you passing it on. But if you have a infection you should stay at home.
While the information is confusing, there does appear to be a moderate beneficial effect to wearing masks in public. But this has to be combined with handwashing and social isolation.
The HSE may advise everyone to wear masks in public in the future. The coronavirus pandemic is new territory for all of us, including the experts and we need to be patient while the science attempts to clarify the issues. For now, the most important things we can do are, wash our hands, cough into a tissue or our elbow, keep our hands away from our face, maintain social distancing and stay at home if we are ill.