COVID-19 prevention: Cloth masks may be effective only if washed daily with hot water

Cloth masks are often re-used for multiple days in a row, and this increases the risk of contamination, warns a study.

Until a COVID-19 vaccine is available, it is crucial to strictly follow the preventive measures such as wearing a face mask, practicing hand hygiene and maintaining social distancing to avoid exposure to the virus or prevent spreading the disease. As surgical masks and N-95 respirators are needed by health care providers, the public is recommended to use cloth masks instead. A cloth mask can trap droplets that are released when the wearer talks, coughs or sneezes. Thus, it helps stop infected people from spreading the virus to others and slow down the transmission of COVID-19. However, cloth masks may be effective in preventing viral infections only if they are washed daily at high temperatures, said researchers.

In a study published in the journal BMJ Open, Professor Raina MacIntyre from the University of New South Wales in Australia stated that both cloth masks and surgical masks should be considered 'contaminated' after use.

While surgical masks are disposed of after use, cloth masks are re-used for multiple days in a row, and this increases the risk of contamination, Maclntyre added.

Wash your cloth masks after every use

The researchers came to the conclusion after analysing data from a randomised controlled trial (RCT) they published in 2015, which they claimed is still the only RCT ever conducted on the efficacy of cloth masks in preventing viral infections.

For the study, the team collected data on whether health workers washed their masks daily, and if so, how they washed their masks. They found that cloth masks were as effective as a surgical mask in preventing viral infections if they were washed in the hospital laundry.

As the study was conducted over five years ago, the analysis included common respiratory pathogens such as influenza, rhinoviruses and seasonal coronaviruses, but not SARS-CoV-2 that causes COVID-19.

Even though someone from the general public wearing a cloth mask is less likely to come into contact with pathogens compared to a healthcare worker in a high-risk ward, the researchers still recommended daily washing of cloth masks in the community.

This is how you should wash your cloth face mask

Handwashing the cloth masks may not provide adequate protection against the virus. According to the analysis, healthcare workers who self-washed their masks by hand had two times higher risk of infection compared to those who used the hospital laundry.

The World Health Organization (WHO) recommends machine washing masks with hot water at 60 degrees Celsius and laundry detergent. Maclntyre said the results of their analysis also support this recommendation.

Based on the analysis, the researchers concluded that cloth masks do work but once it has been worn, it needs to be washed properly before being worn again, otherwise it stops being effective.

When you should wear a cloth face mask?

The U.S. Centers for Disease Control and Prevention (CDC) recommends wearing a cloth face mask when you're around people who don't live with you and in public settings when social distancing is difficult. Make sure you wash or sanitize your hands before and after putting on and taking off your mask. Here are a few other things to keep in mind while putting on and taking off a cloth mask:

• Your mask should cover your mouth and nose properly.
• Avoid touching your mask while wearing it. When touched accidentally, wash or sanitize your hands.
• Don't wear wet or dirty masks. When you change your mask, put the used mask in a sealable bag until you can wash it.
• While removing the mask, untie it or lift off the ear loops without touching the front of the mask or your face.
• Wash your hands immediately after removing your mask.

With inputs from agencies