FactCheck: No, these claims in an anti-mask leaflet delivered to homes aren't true

A leaflet by Anti-Corruption Ireland contains a list of false statements about masks and their effectiveness.

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A LEAFLET DISTRIBUTED by Anti-Corruption Ireland, an anti-government group, contains a series of false claims about face masks and how effective they are against the spread of Covid-19.

Misinformation printed on the leaflet about masks’ effectiveness and their impact on the wearer suggests that people should “know the dangers” and “say no” to wearing masks.

The leaflet contains a list of false statements about masks which fall under three key themes:

  1. Masks reduce your oxygen intake;
  2. Masks are a “breeding ground” for germs;
  3. There are no scientific studies to show masks are effective at preventing infection.

All of these claims are untrue – let’s take a look at why.

Claim: Masks reduce your oxygen intake

Evidence: Masks that are worn properly do not reduce a person’s oxygen levels.

The World Health Organisation (WHO) has stated that wearing disposable masks does not negatively affect one’s oxygen intake.

In relation to the common blue pleated masks, it advises that the “prolonged use of medical masks can be uncomfortable”, but that doing so “does not lead to C02 [carbon dioxide] intoxication nor oxygen deficiency”.

FACT-_The_prolonged_use_of_medical_masks__when_properly_worn,_DOES_NOT_cause_CO2_intoxication_nor_oxygen_deficiency World Health Organisation World Health Organisation

“While wearing a medical mask, make sure it fits properly and that it is tight enough to allow you to breathe normally. Do not re-use a disposable mask and always change it as soon as it gets damp.”

World Health Organization (WHO) / YouTube

The WHO has also issued advice on how to properly wear disposable masks and cloth or non-medical masks.

And a study published late last year found that even wearing a face covering during intense exercise is not dangerous for oxygen levels.

The study, which was published by the International Journal of Environmental Research and Public Health, found no evidence that could support concerns that wearing a face covering could hinder oxygen intake or increase breathing in carbon dioxide during exercise.

Participants in the study were monitored as they exercised in three different scenarios: while wearing a surgical mask; while wearing a three-layer cloth mask; and while wearing no mask at all.

The researchers said that their findings indicated that people “can wear face masks during intense exercise with no detrimental effects on performance and minimal impact on blood and muscle oxygenation”.

Another study, published in January, looked at carbon dioxide and oxygen levels after mask-wearing in both in healthy individuals and people with chronic obstructive pulmonary disease (COPD).

Participants were examined while they were resting after they had worn a mask for five minutes and again after they had worn a mask for 30 minutes. 

That study found that “gas exchange is not significantly affected by the use of surgical masks, even in subjects with severe lung impairment”.

The claim that wearing masks reduce oxygen intake in therefore false

Claim: Masks are a “breeding ground” for germs

Evidence: Wearing a mask correctly and in line with public health advice does not put the wearer at risk of germs.

The suggestion that masks can harbour germs and impact a person’s health has been circulating since the start of the pandemic and is designed to undermine public health measures.

For example, false claims that masks contain parasites or that they can cause bacterial pneumonia have been spread widely on social media, but both are untrue.

The particular claim made in the Anti-Corruption Ireland leaflet centres on the suggestion that germs or bacteria can grow inside masks because they become moist after people wear them.

However, this does not happen when you wear a face mask safely and wash reusable masks regularly, as most people do.  

Speaking to The Journal, virologist Dr Kim Roberts said that “when worn correctly, both disposable face masks and reusable face coverings are very safe and in many settings can reduce the risks of SARS-CoV-2 transmission”.

“Disposable masks are designed for single use and should be discarded after one use or when wet, whichever is first. Reusable masks and face coverings should be washed after each use, to remove any SARS-COV-2 and any other viruses and bacteria that might be present in the fabric,” Dr Roberts said.

“It might be reassuring to remember that long before this pandemic, health care professionals routinely wear face masks for many hours at a time safely,” she said.

shutterstock_1846752421 Shutterstock / Juice Verve Shutterstock / Juice Verve / Juice Verve

“To get the best protection, face masks and face coverings should be made from at least three layers of material and fit snugly over the nose and mouth with no gaps.”

As Dr Roberts said, masks can come into contact with bacteria or virus particles, which is why we wash reusable masks or throw away disposable ones – but it would take a substantial lack of hygiene for it to become a problem.

Any risk of becoming ill from germs on a mask is significantly lower than the risk of contracting Covid-19, which can cause serious illness, and The Journal has previously debunked similar claims that mask-wearing caused a spike in respiratory diseases, such as pleurisy or Legionnaire’s disease.

Public health organisations have set out clear guidelines that reusable masks, such as cloth masks, should be washed frequently with soap and hot water.

Like any other item you might wear, masks can get dirty when they are used. Not washing them would be unhygienic – but the fact that they need to be washed doesn’t mean that they are broadly unsafe to use. 

The HSE advises storing a mask that is wet or dirty from sweat, saliva, make up or another substance in a sealed plastic bag until it can be washed.

“Wash your cloth face covering whenever it gets dirty or at least daily,” it recommends. 

If a reusable face covering has holes or tears in the fabric, it should be disposed of.

Disposable masks are single-use and should be thrown away when you’re finished wearing them.

This is because they are designed in a way that makes them best suited to being worn once, whereas reusable masks that are made of washable fabrics can be cleaned and worn again.

Given the evidence available, the claim that masks are a “breeding ground” for germs is misleading.

Claim: There are no scientific studies to show that masks are effective at preventing infection

Evidence: Scientific evidence shows that masks can help to reduce the spread of infectious diseases.

Since the start of the pandemic, a range of studies have been carried out on masks’ effectiveness against Covid-19.

Health organisations around the world, including the WHO, the US-based Centres for Disease Control and Prevention (CDC), and the HSE, all recommend the use of masks as a way to help prevent the spread of the virus. 

There are two ways that masks can block transmission of Covid-19.

The first is by blocking particles, which could contain the virus and spread it to others, that a person exhales. These particles are blocked when a person wears a mask.

Secondly, masks can also reduce the droplets that a person breathes in by filtering droplets and particles from outside their mask.

A review of evidence for using face masks against Covid-19 was published by the National Academy of Sciences in the US in January.

The review looked at a wide range of studies to consider evidence on the efficacy of wearing masks in public; the impact of mask requirements in countries where a mandate is in place; whether an infectious person can decrease the number of people they infect by wearing a mask; and whether a person’s risk of becoming infected can be reduced by mask-wearing.

It found that evidence favoured the wearing of masks as an effective tool to reduce community transmission of Covid-19.

“The available evidence suggests that near-universal adoption of non-medical masks when out in public, in combination with complementary public health measures, could successfully reduce R [the effective reproduction number] to below 1, thereby reducing community spread if such measures are sustained,” the study said.

“When used in conjunction with widespread testing, contact tracing, quarantining of anyone that may be infected, hand-washing, and physical distancing, face masks are a valuable tool to reduce community transmission.”

Additionally, many studies have been carried out into how specific types of masks can protect against Covid-19 in different settings.

A study from September 2020 tested different types of disposable and cloth masks to look at the effectiveness of face coverings made from common fabrics.

In relation to cloth masks, the study said:

Mask wearing in the general population with a well-designed cloth mask can flatten the curve in areas of high incidence and should be used in combination with other non-pharmaceutical options such as social distancing and hand hygiene. 

The claim that there are no scientific studies to show that masks are effective at preventing infection is therefore false.

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