Many private businesses and some states are plowing ahead with methods of verifying that people have been vaccinated, despite conservative resistance to "vaccine passports."

Why it matters: Many businesses view some sort of vaccine verification system as key to getting back to normal. But in the absence of federal leadership, a confusing patchwork approach is likely to pop up.

The big picture: “I think it’s going to be a tidal wave that’s going to be very difficult to stop, because there’s enormous economic and social incentive for proof of vaccinations,” said Lawrence Gostin, a professor at Georgetown University.

• Although he agrees with the approach of letting states and the private sector lead, Gostin thinks the federal government should have a larger advisory role.
• “Unless they provide national scientific guidance and technical assistance, we’re going to see a patchwork of variable quality across the country,” he said. “And we’ve seen that movie before…you get a mess.”

Where it stands: The Biden administration has said that it will not mandate vaccine passports across the country, nor will it create a federal vaccination database. That leaves decision-making to the states and the private sector.

• But several Republican governors already said they'll fight any such systems.
• In Texas, Gov. Greg Abbott signed an executive order banning state government and some private businesses that receive public funding from requiring proof of Covid-19 vaccination.
• In Florida, Gov. Ron DeSantis banned the use of Covid-19 vaccine credentials through an executive order.

The other side: Many private companies have already begun planning ways to verify that their customers have been vaccinated.

• New York has also rolled out a pass that sports and entertainment venues can use if they choose, and Hawaii is working on a vaccine passport that would let travelers bypass a two-week quarantine.

Between the lines: Requiring proof of vaccination is likely on solid legal ground, experts said.

• "In general, private businesses can decide who they're willing to admit into their businesses and serve so long as they don't violate either the federal Civil Rights act or a state law," University of Pennsylvania professor Eric Feldman told Axios.
• “Just like you can say no shirt no shoes no service, you can say no vaccine no service,” Gostin said, adding that he thinks the Florida ban would likely lose if challenged in court.

Where it stands: Online services, universities, airlines, and retailers are figuring out how and whether to provide proof of vaccination for students, customers and employees.

• For online caretaker services, that can mean an optional "vaccination badge" for potential babysitters, which is what Urban Sitter is doing.
• Pet-sitting site Rover told Axios that it has seen an increase in sitters proactively adding information about their vaccine status on their profile pages, and they're considering more formal ways for sitters to add such information if they want, spokesman David Rosenbaum said.
• The list of universities in the U.S. requiring proof of vaccination is growing.

What we’re watching: Experts worry that vaccine verifications could end up deepening existing inequities, as vaccination rates among people of color lag behind those of white people in the U.S.

• But they generally don’t worry about whether they’re justified.
• "There seems to be a pretty clear public health justification for trying to ensure that those who are gathering in places where an airborne transmissible virus that could lead to sickness or the death of others, that you want to take the necessary precautions," Feldman said. "One precaution is to screen some people in and screen some people out."

The bottom line: Proponents of vaccine verifications say they’ll ultimately be driven by economics.

• “Unless a business can create a safe environment for its employees and its customers, the employees and the customers won’t come in,” Gostin said.