Publix, Walmart, Sam's Club, Costco and Trader Joe's announced Friday that facial coverings are now optional for shoppers who are fully vaccinated. Trader Joe's has also lifted mask restrictions for vaccinated customers. The stores cite the CDC's new guidance relaxing mask restrictions for inoculated individuals as the reason for modified mask policies. What does it mean to be "fully vaccinated"? According to the CDC, an individual is deemed "fully vaccinated" two weeks after receiving the second dose of the Pfizer or Moderna vaccine, or two weeks after receiving the single-dose Johnson & Johnson vaccine. What if there's a state or local mask mandate?