Cloth masks are not equivalent to medical-grade masks and should not be recommended for health care workers, researchers said on Wednesday.
A group of researchers from the University of New South Wales in Sydney Australia published the result after conducting a randomized controlled trial on the healthcare workers of Vietnam in 2015, reports CNN.
The workers were checked for influenza-like illnesses, which include a range of respiratory infections - wrote Dr Abrar Chughtai, an epidemiologist and his colleagues in the journal Emerging Infectious Diseases
"Rates of infection were consistently higher among those in the cloth mask group than in the medical mask and control groups. This finding suggests that risk for infection was higher for those wearing cloth masks," said the researchers.
"The mask tested was a locally manufactured, double-layered cotton mask. Participants were given five cloth masks for a 4-week study period and were asked to wash the masks daily with soap and water. The poor performance may have been because the masks were not washed frequently enough or because they became moist and contaminated."
The team also reviewed 19 other studies of masks and found the fabric used is important saying effectiveness of a cloth masks depends on many factors.
"Current evidence suggests that multilayered masks with water-resistant fabric, high number of threads, and finer weave may be more protective." they mentioned.
The researchers said that for coronavirus, all frontline health care workers should wear medical masks or N95 respirators.
"During a pandemic, cloth masks may be the only option available; however, they should be used as a last resort when medical masks and respirators are not available," they concluded.