Aug 20 (Reuters) - The resurgence of COVID-19 cases in the United States due to the Delta variant and the new guidance from the U.S. Centers for Disease Control and Prevention (CDC) that requires fully vaccinated individuals to wear masks have led companies to change their plans on vaccinations and masking. Here are some of the companies that have taken action following the CDC guidance. COMPANY ACTION Walmart Inc (WMT.N) Reinstated mask mandate for workers in U.S. counties deemed at high risk of COVID-19 transmission and said it required corporate staff to be vaccinated Apple Inc (AAPL.O) Mandated masks at most of its U.S. retail stores Amazon.com Inc (AMZN.O) Asked all U.S. employees to wear masks at work, regardless of their vaccination status Target Corp (TGT.N) Mandated masks for employees and recommended masks for all customers in areas with a high risk of transmission Home Depot Inc (HD.N) Mandated employees, contractors and vendors to wear masks in all stores, distribution centers, office locations and customers" homes, regardless of vaccination status. Will also ask customers to wear masks while in stores Alphabet Inc (GOOGL.O) Mandated vaccinations for all employees to step into offices and extended work-from-home policy through Oct. 18 Facebook Inc (FB.O) Mandated vaccinations for all employees to step into offices Twitter Inc (TWTR.N) Shut its reopened offices and paused future office reopenings Lyft Inc (LYFT.O) Mandated vaccinations for employees returning to office and postponed office reopenings to February from September Netflix Inc (NFLX.O) Mandated vaccinations for cast and crew on all its U.S productions Salesforce.com (CRM.N) Mandated vaccinations for employees to return to some of its offices Walt Disney Inc (DIS.N) Mandated mask requirements beginning July 30 for all guests while indoors regardless of their vaccination status, and that all salaried and non-union hourly U.S. employees working at any of its sites be fully vaccinated Verizon Communications Inc (VZ.N) Requires all U.S employees to wear a mask while indoors. Retail staff to wear face coverings when on the store floor. AT & T Inc (T.N) Employees who come in to work locations in areas with high or substantial transmission of COVID-19 are required to wear face masks regardless of vaccination status. Management employees need to be vaccinated before entering a work location. LinkedIn Corp To allow most employees to opt for full-time remote work as offices gradually reopen U.S. automakers General Motors Co (GM.N), Ford Motor Co (F.N) and Stellantis NV (STLA.MI) to reinstate the wearing of masks at all U.S. plants, offices and warehouses, regardless of vaccination status McDonald"s Corp (MCD.N) Mandated all U.S.-based office workers to be vaccinated, and all customers and staff to wear masks inside its U.S. restaurants in areas with high or substantial transmission New York Stock Exchange (ICE.N) Anyone accessing its trading floor at 11 Wall Street needs to be fully vaccinated Morgan Stanley (MS.N) Staff and clients will not be allowed to enter the bank"s New York offices if not fully vaccinated Jefferies Group Will allow only fully vaccinated individuals into offices and events hosted outside offices Uber Technologies Inc (UBER.N) Mandated full vaccination for all employees to step into office and pushed back its back-to-office date to late October globally Tyson Foods Inc (TSN.N) Mandated full vaccination for its workforce Gap Inc (GPS.N) Employees entering its office buildings in Bay Area, New York, and Albuquerque hubs must show proof of vaccination starting Sept. 7 Kohls Corp (KSS.N) Employees in counties with high risk of transmission need to wear masks while in store CVS Health Corp (CVS.N) All employees to wear a face mask or covering in all CVS health worksites Gilead Sciences Inc (GILD.O) All its employees and contractors in the United States need to be vaccinated Pfizer inc (PFE.N) All U.S. employees and contractors must get vaccinated or participate in weekly COVID-19 testing Moderna Inc (MRNA.O) All U.S. employees will require vaccinations against COVID-19 from October. The company said it would make religious or medical exemptions on an individual basis. Microsoft Corp (MSFT.O) All employees, vendors and guests will be required to show proof of COVID-19 vaccination to enter company"s U.S. buildings United Airlines Inc (UAL.O) Mandated all its U.S.-based employees to be fully vaccinated against COVID-19 and show proof of vaccination Citigroup Inc (C.N) U.S. employees returning to its New York headquarters and offices in some cities required to be vaccinated JPMorgan Chase & Co (JPM.N) Mandated masks for employees in U.S. offices regardless of their vaccination status Centene Corp (CNC.N) All employees will have to show proof of vaccination or undergo regular COVID-19 tests and wear masks at all times while in company offices Caterpillar Inc (CAT.N) Reintroduced mask mandates for employees, suppliers and visitors to the company"s facilities regardless of their vaccination status Deere & Co (DE.N) Mandated masks for employees, suppliers, and visitors to its facilities regardless of their vaccination status