The US Centres for Disease Control and Prevention (CDC) has revised its guidance for Americans on wearing masks to protect against Covid-19, recommending donning “the most protective mask you can” while stopping short of advocating nationwide usage of N95 respirators.

The CDC, an agency critics have accused of offering shifting and confusing guidance amid the pandemic, clarified on its website “that people can choose respirators such as N95s and KN95s, including removing concerns related to supply shortages for N95s.”

Americans should “wear the most protective mask you can that fits well and that you will wear consistently,” the CDC added.

The CDC said it wants to encourage Americans to wear masks rather than push them to wear the highest-grade face protection, but also explicitly said that respirators provide the best level of protection. It said that “loosely woven cloth products provide the least protection.”