Although the U.S. government does not require everyone to get Covid-19 vaccines for their protection, large corporations across America are filling this void.Over a dozen major U.S. companies, including Walmart, Tyson Foods, United Airlines and Google, recently announced mandates to provide vaccines to some or all their employees."With rapidly increasing COVID-19 cases of contagious, deadly variants leading to increasing rates for severe illness and hospitalization among U.S. non-vaccinated populations, it is time to take next steps to ensure a fully vaccinated workforce," Tyson's chief physician, Dr. Claudia Coplein, stated in a Tuesday statement.According to Johns Hopkins University data, the U.S. had a 7-day average of over 108,600 new cases per days as of Sunday. This is 36% more than a week ago. According to Centers for Disease Control and Prevention estimates that 83% of all sequenced coronavirus infections in the United States stem from the delta variant, vaccines are considered the best way to bring employees back to work.Although some employers have now decided to mandate vaccinations unilaterally, many others have restricted their guidance to specific offices or groups of workers.Google and Facebook require Covid vaccinations for all Americans who return to their U.S. offices. Walmart, with 1.6 million employees in the United States, has established a mandatory vaccine mandate for all managers and corporate employees. Store employees must wear masks to high-risk countries.Doug McMillon, Walmart CEO, outlined Walmart's plans to continue "gradually returning into our offices with the idea to be closer to pre-pandemic level after Labor Day."Gallup polled 70% of respondents to its April 2020 survey who were working remotely. While companies are trying to bring back their workforce, some have begun moving back their return dates due to rising Covid cases. Google delayed its Oct. 18 deadline by more than a month last month.Dr. Stephen Morse is a Columbia University Irving Medical Center professor of epidemiology. He said, "I don't like mandates but we need to use various incentives to encourage people to practice effective infect control." "If this is the only or best way to motivate people, then that's our one tool."United Airlines announced Friday that all its approximately 67,000 U.S. employees must show proof of vaccination against Covid by Oct. 25, making it the country's first major airline. Failure to comply could result in employees being fired. However, United stated that there will be exceptions for religious and medical reasons."We are aware that some of you may not agree with this decision to require vaccine for all United employees," Scott Kirby, United Airlines CEO, and Brett Hart, the airline president, wrote to employees to announce the requirement. "But, we have no greater obligation to you or your colleagues than to make sure your safety at work. The facts are clear: everyone is safer if everyone is vaccinated."Frontier Airlines, a budget carrier, followed the example of Frontier Airlines hours later. It issued its own mandate and stated that employees must either show proof of vaccination by Oct. 1, or undergo regular Covid testing.Vaccines and other tools that fight the virus, such as masks have been controversial in the U.S. However, health officials insist that the measures are needed to save lives."To leave it up the individual is to admit that there are people who will make a decision that puts coworkers at risk," Dr. Paul Offit, an infectious diseases physician at Children's Hospital Philadelphia, said. "So it's something I believe is responsible, important and necessary."Even the largest mandates of companies are subject to law and must allow for some exceptions.Lori Goler (Vice President of People at Facebook) stated that the company, which has nearly 59,000 employees around the world, will have a process for people who cannot be vaccinated due to medical reasons. She also said that experts are working with Facebook "to ensure our returns to office plans prioritize safety and health for everyone."Alphabet Workers Union represents more than 800 employees at Google and its parent company. It expressed concern about the exceptions to Google’s vaccine mandate. The union said that Google has not provided sufficient details regarding the exemption process. The union spokesperson stated that the mandate is intended to "inspire white collar workers to return to the office", while "a boatload" of people remain unvaccinated.Google didn't respond to a request for comments. Alphabet had more than 135,000 employees around the world as of last year.Unions have also criticized vaccine directives issued by other companies. United Food and Commercial Workers representing 24,000 Tyson meatpacking workers expressed reservations after Tyson announced that 120,000 of its employees must be vaccinated.Marc Perrone, President of UFCW International stated that he would meet with Tyson to discuss the vaccine mandate and ensure that workers' rights are protected and that this policy is fairly implemented. Perrone said that he would ensure Tyson's workers get paid time off to adjust to the vaccine and receive it.