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Introduction

This policy note expands on the CMO advice of 5th June, summarising the emerging evidence on potential benefits and risks, concluding that Welsh Government should support the public’s right to choose to wear face coverings in most settings. Advice is provided on when face coverings or medical face masks could be recommended.

Over the past month there has been extensive national and international debate and the emergence of different policy positions across the UK. Little has changed in our understanding of the basic science but the following significant issues have bearing on our choices in Wales.

Updated WHO guidance

  1. There is no new evidence to suggest that everyone in a hospital or care setting should wear masks.
  2. Although there is no new evidence, the WHO has moved to recommending the wearing of face coverings in the community, by the general public in certain situations, but only for source control using a risk-based approach and not for prevention.
  3. There is new guidance on non-medical mask features and characteristics, including choice of fabric, number and combination of layers, shape, coating and maintenance.
  4. The new document continues to emphasise:

"the use of a mask alone is insufficient to provide an adequate level of protection or source control, and other personal and community level measures should also be adopted to suppress transmission"

  1. It is noted that at the present time, the widespread use of masks by healthy people in the community setting is not yet supported by high quality or direct scientific evidence and there are potential benefits and harms to consider.
  2. WHO has recommended that in areas of community transmission, governments should encourage the general public to wear masks in specific situations and settings as part of a comprehensive approach to suppress the risk of SARS-CoV-2 transmission.
  3. WHO recommended that those with symptoms wear surgical masks and continue to practice self-isolation and hand-hygiene.

Implications

CMO advice continues to be that the evidence of benefits does not justify a mandatory or legislative process and that there would be potential dangers in taking such an approach in Wales.

Clear public messaging is needed to avoid potential harms from use of face coverings; this should address public understanding on the need for social distancing and the avoidance of face touching; advice on hand washing and surface cleaning continues to be of paramount importance.

  1. The importance of the hierarchy of measures which must be in place in order to reduce person to person transmission remains. In order of importance and effectiveness these are:
    1. Elimination of unnecessary activities
    2. Substitution of less risky behavioural patterns
    3. Engineering controls
    4. Administration controls
    5. PPE
  2. With regard to face coverings a settings-based risk assessment approach is advised.

Use of face coverings by the general public

The WHO continues to advise that the widespread use of masks by healthy people in the community setting is not yet supported by high quality or direct scientific evidence and there are potential benefits and harms to consider.

  1. However, WHO has updated its guidance to advise that, to prevent COVID-19 transmission effectively in areas of community transmission, governments should encourage the general public to wear masks in specific situations as part of a comprehensive approach.
  2. Advice needs to be more or less directive depending on the risk from particular settings, the extent to which other mitigations are available and in place, and the level of viral transmission. Suggested policy recommendations are set out below:
    Risk level Setting Recommendation
    Moderate risk (confined indoor spaces)
    • Public transport if overcrowded
    • Shops if overcrowded
    Recommend face coverings be worn by the general public
    Less risk (indoor spaces where social distance can be maintained)
    • Public transport which is not overcrowded ie social distancing can be maintained
    • Retail outlets where re-engineering of space has allowed the maintenance of social distancing
    • School and (non-healthcare) work environments with social distance marking
    • Non-clinical areas on healthcare work environments
    Face coverings not recommended
    Least risk (outdoor spaces) where social distancing should be maintained
    • Parks, gardens
    • Trails, paths, roads
    Face coverings not recommended
    • Clear guidance should be provided to ensure that face coverings meet a minimum standard, as well as advice about how they should be worn and washed or disposed.
    • Clear guidance should be provided on who should not or cannot wear face coverings (e.g. elderly people with cognitive impairment, young children).
    • The use of a face covering should not be seen as a substitute for observing other infection control measures including self-isolation, hand washing and social distancing.
  3. The Nosocomial Transmission Group has considered the use of medical and face coverings and recommends the following:
    • Medical masks should, in the main, still be for use by health and social care workers in direct care of patients / residents. Evidence is not strong enough to suggest medical masks should be used in non-clinical settings. 
    • Healthcare workers should social distance, with good hand hygiene and respiratory etiquette but the evidence does not support the wearing of medical masks in non-clinical areas.
    • The group did not support the need for hospital staff to wear medical masks in non-clinical areas
    • Unlike in England, NHS organisations in Wales are under a legal duty to implement social distancing measures for employees wherever possible and we have provided detailed operational guidance on the estates and environmental measures required to achieve this. In non-patient facing areas staff need to be supported to social distance effectively, potentially with re-arrangements of office spaces and tea rooms for example.
    • There is still room for improving the use of PPE and its correct removal with hand hygiene as current recommendations.
    • Should people on the Welsh shielded list need to attend an out-patient appointment or diagnostic procedure then they should use a medical mask. NHS organisations will need to provide medical masks to the shielded community as required. The need for those who are shielding to attend health and care settings should be minimised and visitors to wards should remain limited

Additional considerations

  1. WHO has clear specifications requiring a minimum 3 layer of material construction. Clear messaging on WHO guidance for face coverings will need to be conveyed to the public.
  2. It is important to reiterate that public guidance should also include messaging around:
    • The continued need for social distancing and hand hygiene and recognition that these are more important than face coverings
    • Not touching your face is important but is more difficult when wearing a face covering
    • Donning and doffing are the most dangerous times to spread infection
    • Keeping Wales tidy and safe when removing face coverings, there is a particular risk to children and animals if they become litter
  3. There will be some issues of equity and diversity which will be difficult to mitigate including the needs of children who often give regard to facial expressions when being spoken to, and those of the hearing impaired who need to lip read.

Dr Frank Atherton
Chief Medical Officer
10 June 2020

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