Ammon News - United Airlines Inc (UAL.O) on Friday became the latest company to require all its U.S.-based employees to be fully vaccinated against COVID-19.

The airline said employees would need to show proof of vaccination, five weeks after the U.S. drug regulator fully approved any of Pfizer Inc, Moderna Inc or Johnson & Johnson's COVID-19 vaccine or by October 25, whichever was earlier.

A resurgence of COVID-19 cases in the United States due to the more infectious Delta variant has forced the U.S. Centers for Disease Control and Prevention to reimpose some mask mandates and some companies to require vaccinations at workplaces.