In a push to get more American workers vaccinated, Joe Biden will meet virtually Wednesday with the chief executives of United Airlines and Kaiser Permanente.

Also expected to attend in Howard University President Wayne Frederick and South Carolina small business Diane Sumpter alongside the CEOs, a White House official told The Wall Street Journal.

The university and companies have already mandated that staff be vaccinated, with Howard also requiring the vaccine for students attending the university. Southwest, American Airlines, and Delta have already said that they will not require employees to get vaccinated.

Biden reportedly plans to highlight the four as a model for other private-sector leaders amidst the push for more Americans to get vaccinated against the highly contagious delta variant spreading across the country.

“The official said the participants reflect four sectors—large corporations, small businesses, healthcare providers, and colleges and universities—that the administration sees as pillars in inoculating the US against the virus,” The Wall Street Journal reported.

The meeting comes in the wake of the Biden Administration recently announcing that federal workers must get vaccinated or be subjected to regular COVID-19 testing, with Biden calling for businesses to follow suit.

Earlier this week, the Treasury Department held a call with 900 employers to discuss the use of funding received from the more than $1 trillion COVID-19 relief plan signed back in March to reportedly give employees time off to get vaccinated.

Led by White House Covid-19 response coordinator Jeff Zients and Office of Public Engagement director Cedric Richmond, administration officials have reportedly also worked with companies to offer incentives to Americans to get the coronavirus vaccine.

Brewer Anheuser-Busch gave away free beers to those vaccinated on July 4, ride share and child-care services reportedly offering other services, and administration officials were in contact with Yelp before they added a filter allowing those searching to filter businesses by “proof of vaccination required” and “all staff fully vaccinated.”

Companies like DisneyUnited, and Google have recently issued vaccine mandates for their employees. According to the American Hospital Association, around 1,500 are requiring their employees to get vaccinated. More than 600 colleges and universities are requiring the vaccine as well, according to the Chronicle of Higher Education.

“We are essentially saying there are different paths you can take, but the path that you cannot take is doing nothing—that’s the one unacceptable position right now,” said deputy director of strategic communication and engagement for Biden’s Covid-19 response team Ben Wakana.

“Businesses, at this point in time, I think, have a unique ability like they have not had at any other time during this pandemic to actually curb the direction of this pandemic,” he continued.

In addition to companies, many states like New York, California, and in the District of Colombia have issued vaccine requirements for their government workers, the Pentagon will also be adding the vaccine to its mandatory list for US service members by mid-September.