Cloth masks provide limited protection for healthcare workers, new study finds

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  • The shortage of personal protective equipment (PPE) in healthcare settings has led to the use of cloth masks
  • Researchers published a review of the efficacy of cloth masks to protect healthcare workers against respiratory viruses like Covid-19
  • Although cloth masks do provide some protection against aerosols, their inferior fit and airflow result in inadequate protection in healthcare settings


Healthcare workers on the frontline of the Covid-19 pandemic have at times experienced a scarcity of personal protective equipment (PPE) leading to the use of cloth masks, the rationing of supplies and extending the use of surgical masks.

Researchers at the University of Colorado’s School of Medicine recently published a review in the Annals of Family Medicine to summarise the evidence for the efficacy of cloth masks to prevent respiratory infections, such as Covid-19, among healthcare workers.

Review methods

The paper explains that the researchers searched five databases; the Centre for Disease Control and Prevention (CDC) website; and the Web of Science Databases to find relevant studies about cloth mask efficacy to conduct the review.

The 136 publications identified by the researchers were screened by two reviewers, and the randomised control trials, observational, and non-human subject studies were graded according to critical appraisal tools, the researchers explain.

Cloth masks' filtration efficacy

The researchers’ review found that cloth materials do prevent the penetration of some particles but have a lesser filtration efficacy than medical and KN-95 masks. Although cloth masks are better than wearing no mask at all, according to the researchers, their filtration variability cannot assure healthcare workers of sufficient protection.

Airflow and fit

Moreover, multiple reviewed studies revealed that, compared to medical face masks, cloth masks showed an inferior fit. A poorly-fitting mask decreases protection because particles can pass through the gaps between the wearer's face and the mask, and poor airflow often leads to difficulty breathing and compliance issues.

“Two studies found that the studied designs and materials of cloth masks limit both proper airflow and fit, leading to decreased protection and breathing difficulties,” according to the researchers.

Overall, they concluded that there is insufficient evidence to prove that cloth masks provide suitable protection for healthcare workers against respiratory infections.

Recommendations

The CDC recommends that healthcare workers wear KN-95 masks when treating patients withCovid-19 due to their protection against aerosolised particles.

In instances where healthcare workers do not have access to medical masks, the researchers recommend pairing the cloth mask with a plastic face shield.

“We recommend frequent cloth mask changes to reduce the risk of moisture retention and washing according to hospital laundry standards to decrease the risk of ineffective cleaning,” the researchers added. 

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