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Cloth Masks Put Health Workers at Risk of Infection

The use of cloth masks by healthcare workers may actually put them at increased risk of respiratory illness and viral infections, according to a University of NSW study published in BMJ Open.

Cloth masks remain widely used across the world because they are a cheaper option, especially in areas where there are shortages of protective equipment, including in Asian countries that have historically been affected by emerging infectious diseases, as well as in West Africa, which was the epicentre of the recent Ebola epidemic.

“Masks are worn to protect from infection during pandemics and outbreaks, especially when there are no drugs or vaccines available for protection,” said lead author Prof Raina MacIntyre. “Masks are especially important for frontline doctors and nurses, as their protection from infection is key to maintaining the ability to tackle a pandemic effectively.

The researchers split 1607 hospital healthcare workers from 14 hospitals in Hanoi into three groups: those wearing medical masks, those wearing cloth masks and a control group based on usual practice, which included mask wearing.

Workers used the mask on every shift for 4 weeks, with respiratory infection occurring much higher among those wearing cloth masks. The penetration of cloth masks by particles was almost 97% compared with 44% for medical masks.

While the study’s results pointed to the effectiveness of medical masks, the authors speculate that the increased risk of infection with cloth masks could be due to their retention of moisture, their reuse and poor filtration capabilities. “Cloth masks should not be used by workers in any healthcare setting, but particularly high-risk situations such as emergency departments, intensive care, paediatric or respiratory wards,” MacIntyre advised.

MacIntyre recently published an expert review in the British Medical Journal in which she found that the lack of research on face masks and respirators is reflected in varied and sometimes conflicting global policies and guidelines. “Despite more than half the world using cloth masks, global disease control guidelines, including those from the World Health Organisation, fail to clearly specify conditions of their use,” she said. “These guidelines need to be updated to reflect the higher infection risk posed by cloth masks, as found in our study.”