Aga Khan University Hospital bans use of masks with valves at its premises

The Aga Khan University Hospital has has banned use of masks with valves within its premises.

In a statement released on Wednesday, the hospital warned that such masks only protect the wearer and offer no protection to those around them.

“The design of these masks allow inhaled air to be filtered but the exhaled air is not. The exhaled air can be expelled towards others even more than from a person not wearing a mask,” AKUH said.

COVID-19 spreads mainly through respiratory droplets when a person talks, sneezes, sings or coughs. Masks can help stop those respiratory droplets.

The World Health Organization (WHO) does not advise using masks or respirators with exhalation valves.

According to the agency, masks with valves are intended for industrial workers to prevent dust and particles from being breathed in as the valve closes on inhale.

However, the valve opens on exhale, making it easier to breathe but also allowing any virus to pass through the valve opening.

“This makes the mask ineffective at preventing the spread of COVID-19 or any other respiratory virus,” a statement on the WHO website reads.

The US Centers for Disease Control and Prevention also does not recommend that people use masks with valves or vents during the Covid-19 pandemic.

According to the agency, the one-way valves may provide the wearer more comfort, since the valves allow air to escape from the mask and can keep people cooler, but the valves also allow the virus to escape from the mask.

Additional reporting from CNN and WHO website