Apple will again require vaccinated customers and staff to wear masks at more than half of its U.S. stores, Bloomberg reported Wednesday.

The tech giant’s decision came after the Centers for Disease Control and Prevention (CDC) on Tuesday advised vaccinated people in areas with high COVID-19 transmission to wear masks indoors, a reversal from its previous guidance. 

“After carefully reviewing the latest CDC recommendations, and analyzing the health and safety data for your local area, we are updating our guidance on face masks for your store,” Apple told staff in a memo obtained by Bloomberg. “Starting July 29, face masks will be required in store for customers and team members — even if they’re vaccinated.” 

Apple is the first major company to announce that it will restore a mask mandate following the new CDC guidance. The iPhone manufacturer said it made the decision out of an abundance of caution. 

Most companies, including Apple, dropped mask mandates at their retail locations after the CDC released guidance in May stating that vaccinated people no longer needed to wear masks.

More stores are expected to restore mask requirements for all customers and staff in areas that are being hit hard by the delta variant. 

Retail Industry Leaders Association President Brian Dodge said in a statement Tuesday that “masks may be necessary again in some circumstances” amid new CDC guidance and a surge in COVID-19 cases. 

CDC Director Rochelle Walensky on Tuesday said that while vaccines are highly effective in combating the delta variant, new data shows that the small percentage of vaccinated individuals who do contract the variant can spread the virus to others.

“We’re seeing now that it’s actually possible if you’re a rare breakthrough infection that you can transmit further, which is the reason for the change,” Walensky told reporters.