Walmart, Sam's Club, Costco, Trader Joe's, and Publix on Friday were among the first major retailers to announce that shoppers fully vaccinated against COVID-19 would no longer have to wear masks in their stores, unless required by state or local law. The change in company policies comes after the Centers for Disease Control and Prevention updated its guidelines earlier this week to say that it's safe for vaccinated people to go maskless indoors in most cases. People who have not received their shots will still need to wear face coverings, though it's not clear how the stores will verify who has been vaccinated. Several other major retailers, including Apple and Target, are keeping their mask requirements in place for now, but said they could update the policies soon.