Should we be wearing masks?

The British government is indicating that there is no change – for the moment – to the policy on whether or not we should wear masks to guard against Coronavirus. The Health Secretary, overseeing the health service in England, Matt Hancock indicated this evening that he is awaiting the results of a meeting being held by SAGE to address the issue.

Health chiefs issued a warning on Tuesday that the government should not order the general public to wear face masks on the grounds that it would jeopardise their availability for medical workers.

With so many different governments and international bodies recommending different measures, and three different types of mask on offer, no wonder there is a great deal of confusion surrounding the issues.

There are three types of mask, and the advantages and disadvantages are laid out in reports by the World Health Organisation (WHO), the US Centre for Disease Control (CDC), and the EU European Centre for Disease Prevention and Control (ECDC).

1) N95 Respirators aka FFP2

The N95 Respirator, also known as FFP2, are not recommended for general use by the WHO or the CDC on the grounds that supplies should be conserved for use by medical professionals.

These respirators are designed to fit the face very closely, forming a seal around the mouth and nose. When fitted properly they block at least 95% of very small particles. As such the WHO recommends their use by medical professionals performing “aerosol-generating procedures”, that is procedures which generate small fast evaporating droplets which leave tiny particles of viruses lingering in the air.

2) Surgical masks – medical masks

Mass wearing of surgical masks, often referred to as medical masks, is not strongly recommended with the WHO, CDC, and ECDC all stating that medical workers must be given priority access to these masks.

In terms of protection these masks do filter out larger particles such as larger droplets of spit or phlegm coughed or sneezed out, but smaller particles may still get through. They also do not cover the sides of the mouth. The WHO says there is “limited evidence” that these masks are effective at protecting those attending mass gatherings or in public, and suggests on balance that they should not be worn as they might encourage people to ignore other necessary safety precautions.

The ECDC has suggested wearing these masks, and cloths masks discussed below, “could be considered” especially in busy areas as a way to reduce transmission, not for protection. It notes that the WHO’s guidelines on ways to mitigate the impact of pandemic influenza does conditionally suggest the use of masks – though this general recommendation may not be effective for SARS-COV-2.

The WHO does recommend symptomatic individuals not in hospital should use medical masks “as much as possible” while also self-isolating at home. Home carers looking after these individuals should wear medical masks when in the same room as them. It also recommends symptomatic individuals should wear masks in health care settings while they are awaiting triage or being transported to the medical facility. This is of course in addition to all the other recommended precautions.

3) Cloth masks – non-medical facemasks

So far there is no expert consensus on how useful cloth masks, non-medical facemasks, are. Especially as they are not produced to a universal medical standard. What evidence there is suggests they do not offer much protection to the wearer, with the WHO and ECDC noting that in medical settings they might even increase the risk of infection.

Nevertheless, a growing number of health authorities are recommending that they can be used to help limit how much people who are asymptomatic, or not yet displaying symptoms, spread the virus. The CDC in the US has recommended their use since 3 April, and an ECDC paper 8 April suggested they could be considered for use. Both agencies say the use should be in settings were social distancing measures are difficult to maintain, but both are keen to emphasise that even if using a cloth mask people should continue to strictly adhere to social distancing and handwashing protocol.

The WHO has, as yet, not adopted a position on the use of cloth masks by the general public on the grounds that they lack sufficient evidence to make a judgement either way. In the meantime the agency is conducting its own research and is encouraging countries which do recommend that the general population wear masks to conduct and share data on their effect.

If you do wear a cloth mask it is recommended that you wash it regularly, 60°C in a standard clothes washer is perfectly adequate. When washing people also must take care to ensure the mask’s covering and fit is not affected.

All the major agencies also firmly state that masks of any sort must be put on and removed correctly and that hands must be washed before putting on any mask and after removing it.