A previous version of this article was based on expert guidance at the time of publication, but as the COVID-19 pandemic has grown in the U.S. in recent weeks, public health thinking around wearing face masks has changed. On March 30, the U.S. Centers for Disease Control and Prevention announced it was reviewing its guidelines for face masks, citing data showing that COVID-19 can be spread by people who are infected but not exhibiting symptoms. Then, on April 3, President Donald Trump announced that the CDC is changing its guidance to include a recommendation that all Americans wear non-medical masks, or fabric that covers a person’s face and nose, when they leave their house.

For details on the latest science and public health guidance around face masks and coronavirus, click here.

The Coronavirus Brief. Everything you need to know about the global spread of COVID-19 Please enter a valid email address. Sign Up Now Check the box if you do not wish to receive promotional offers via email from TIME. You can unsubscribe at any time. By signing up you are agreeing to our Terms of Use and Privacy Policy . This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply. Thank you! For your security, we've sent a confirmation email to the address you entered. Click the link to confirm your subscription and begin receiving our newsletters. If you don't get the confirmation within 10 minutes, please check your spam folder.

Write to Mahita Gajanan at mahita.gajanan@time.com.