With the UK experiencing a sharp rise in flu cases, health leaders are once again urging the public to consider wearing masks, particularly those people with symptoms.
The advice stops short of a national mandate but reflects growing concern within the NHS about rising hospital admissions. So what do we know about the effectiveness of masks? And how should they be used?
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What is the guidance?
The UK Health Security Agency says people with flu-like symptoms should stay at home. If they really need to go out, they are asked to wear a mask.
It also advises people to get vaccinated if they are eligible, to open a window for fresh air if they are meeting indoors (and it’s not too cold), and to practise good hygiene. That means coughing into a bent elbow, or using a tissue that is quickly disposed of in the nearest bin. People are advised to wash their hands frequently with warm water and soap, and to clean their “surroundings often, especially areas that are touched frequently such as door handles”.
Several hospital trusts have reinstated masks for staff, patients and visitors in clinical areas. Some NHS leaders have used stronger language, saying individuals with symptoms “must” wear masks, but official guidance remains advisory rather than compulsory.
Do masks protect individuals?
Research suggests masks can offer meaningful protection, but it depends a lot on what kind of mask is worn and how it is used.
Respirators such as N95 or FFP2 masks provide the strongest defence, filtering out a high proportion of airborne particles when properly fitted. Surgical masks can reduce exposure to droplets and aerosols. However, they are primarily designed for “source control” — that is, preventing the wearer from spreading large droplets. Homemade cloth masks are also likely to be less effective.
The FFP2 mask
GETTY IMAGES
Reviews of the evidence point to a general trend: proper mask use is associated with lower transmission of respiratory viruses.
For instance, one “meta study” — a study of studies — published in the journal Disaster Medicine and Public Health Preparedness in 2023 brought together the results of seven previous pieces of research. It concluded that mask-wearing in community settings — those studied ranged from university residence halls to Hajj pilgrimages and ordinary households — was linked to a 17 per cent decrease in the risk of catching an “influenza-like illness”.
Studies suggest protection will be stronger when masks are used consistently and combined with other measures such as proper hand washing.
During the Covid-19 pandemic many people got used to wearing masks in the UK, where they had previously been a rare sight, even during nasty flu outbreaks. A review of studies carried out during the pandemic, overseen by Wanderley Marques Bernardo of the Brazilian Medical Association, suggested that masks helped to prevent Covid infections, but came with the warning that most of those studies were of low quality.
Do mandates work?
The evidence here is less clear-cut. Making masks compulsory can only work insofar as the public sticks to the rules. Another meta study published last year in the journal Clinical Microbiology Reviews concluded they can help reduce infections. The benefits will vary with mask quality and how they are used, however. That study also pointed out that “masks are not generally harmful to the general population” but noted that some groups, notably deaf people, were disadvantaged when others were masked.
For now, ministers show no appetite for broad legal requirements. The emphasis remains on voluntary action and personal responsibility.
What type of mask should you use?
For personal protection, products such as N95 or FFP2 masks are the gold standard. Surgical masks provide less protection but can be more comfortable for longer wear.
How to wear a mask properly?
A well-fitted mask is far more effective. Hands should be washed properly before putting a mask on, and the mask must cover both nose and mouth with no gaps at the sides. Avoid touching the front while wearing it. Disposable masks should be discarded after use. Remove masks using the straps rather than the face covering itself.