Starbucks and McDonald’s revise mask guidance for vaccinated customers

Next time you visit a Starbucks or McDonald's, you might want to bring a face mask.

After loosening mask requirements in May, the two popular chains are now changing their guidance once again as the delta variant continues to spread across the country, as first reported by Food & Wine.

A new Starbucks news post outlines the preventative measures the coffee chain is taking to protect its employees and customers, including the use of facial coverings.

"Starbucks remains committed to meeting or exceeding all public health mandates, as it is our responsibility to protect our partners and customers in the communities we serve," the blog reads. "In alignment with the updated guidance from the CDC, Starbucks strongly recommends customers wear facial coverings while visiting our stores, regardless of vaccination status."

The post goes on to explain that Starbucks will require customers to wear masks in stores where it is "mandated by local law or regulation." As of August 5, all Starbucks employees are now also required to wear masks while working, whether they are vaccinated or not.

Related: The CDC director said the decision to call a return to mask use wasn't taken lightly, and that she hopes it will be temporary.

McDonald's has altered its mask policy too, and recently updated its website to announce that face coverings are required for all customers, regardless of local guidelines.

"McDonald’s asks every customer entering our restaurants to wear a mask or face covering as a safety step based on the most recent guidance from the Centers for Disease Control (CDC)," the site reads.

The COVID-19 safety protocols page also offers insight into the safety measures it has in place for its staff, including the required use of masks and gloves for employees.

"You will notice restaurant crew wearing gloves and face coverings for safety, this is just another way we can help protect our guests and crew members," the page reads.

These latest policy changes from the two major chains come after the Centers for Disease Control and Prevention issued new guidance in July that recommended indoor mask use in areas with high transmission rates. At the time, new data was beginning to suggest that fully vaccinated people can contract COVID-19 and potentially infect others.

Related: One epidemiologist said that unvaccinated indoor diners increase the "level of risk of transmission" for everyone.

With COVID-19 cases on the rise across the country, some experts are also recommending that unvaccinated individuals avoid indoor dining.

"As an unvaccinated person, you are much more likely to be infected, you're much more likely to transmit it to more people. The kind of networks that you get into when indoor dining are themselves quite dicey," Dr. William Hanage, an associate professor of epidemiology at the Harvard T.H. Chan School of Public Health, told TODAY Food last week.