Cloth masks may up risk of infections: study

The use of cloth masks by healthcare workers may actually put them at increased risk of respiratory illness and viral infections and their global use should be discouraged, according to a new study.
The findings come from the first randomised clinical trial to study the efficacy of cloth masks conducted by the University of New South Wales (UNSW).
The trial split 1,607 hospital healthcare workers across 14 hospitals in the Vietnamese capital, 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 four consecutive weeks.

The study found respiratory infection was much higher among healthcare workers wearing cloth masks.
The penetration of cloth masks by particles was almost 97 per cent compared to medical masks with 44 per cent.

Professor Raina MacIntyre, lead study author and head of UNSW's School of Public Health and Community Medicine, said the results of the study caution against the use of cloth masks.
Cloth masks remain widely used globally because they are a cheaper option especially in areas where there are shortages of protective equipment, including in Asian countries, which have historically been affected by emerging infectious diseases, as well as in West Africa, which was the epicentre of the recent Ebola epidemic, researchers said.

Researchers speculate that the cloth masks' moisture retention, their reuse and poor filtration may explain the increased risk of infection.
MacIntyre said emerging infectious diseases are not constrained within geographical borders.
"Effective controls of outbreaks and pandemics at the origin impacts us directly, so it is important for global disease control that the use of cloth masks be discouraged in high-risk situations," MacIntyre said.
The study was published in the journal BMJ Open.