Those states joined several others that have pushed back against vaccination certification, arguing that it violates privacy and civil rights. The Biden administration has said it won't build a national vaccination app, but private companies are racing to create digital "passports" that show proof of immunization.
The government said that as of Sunday, half of all adults in the U.S. had had at least one vaccine shot. About 32.5 percent of the population has been fully vaccinated, the Centers for Disease Control and Prevention reported.
Lawrence Gostin, director of the O'Neill Institute for National and Global Health Law at Georgetown University, previously told NBC News that states' executive orders are unlikely to have much impact.
"Governors have no power to prohibit cities or counties from issuing passports or banning the private sector," he said. "But if the Florida or other state legislature passed a law, it could preempt local governments from issuing passports."
President Joe Biden's chief medical adviser, Dr. Anthony Fauci, told Politico that the federal government won't mandate vaccine passports for businesses or travelers.
White House press secretary Jen Psaki told reporters last week, "Development of a vaccine passport, or whatever you want to call it, will be driven by the private sector." She said the administration does plan to provide recommendations for digital vaccination certificates so there are applicable standards nationwide.
Such "passports," which have been under consideration by the private sector for months, could be scannable QR codes that people could pull up on their phones or simpler green check marks or red X's.
Arizona Gov. Doug Ducey, a Republican, signed an executive order Monday banning vaccine passports and preventing state and local governments from asking people to provide their vaccination statuses to receive services or access to facilities.
"The residents of our state should not be required by the government to share their private medical information," Ducey said. "While we strongly recommend all Arizonans get the Covid-19 vaccine, it's not mandated in our state — and it never will be."
The order doesn't apply to private businesses. Health care institutions, child care centers, schools and universities are authorized to collect vaccination records under state law. The order also permits state and local health departments to require people to provide evidence of vaccination "during a Covid-19 outbreak investigation."
Similarly, Montana Gov. Greg Gianforte, a Republican, issued an executive order prohibiting the development and use of vaccine passports. Under the order, the state and businesses are barred from requiring people to share whether they have been vaccinated.
The ban protects "individual liberty and personal privacy," said Gianforte, who also encouraged Montanans to get vaccinated.
Idaho Gov. Brad Little, a Republican, issued an executive order prohibiting government entities from mandating such documents or verification of vaccination to receive public services or access to facilities.
"Vaccine passports create different classes of citizens," Little said in a statement. "Vaccine passports threaten individual freedom and patient privacy."
Republican Gov. Greg Abbott signed an executive order April 6 barring government agencies from requiring people to be vaccinated or show proof of immunization. It says public and private institutions that receive government funding can't deny someone who fails to show documentation of vaccination.
"As I have said all along, these vaccines are always voluntary and never forced," Abbott said. "Government should not require any Texan to show proof of vaccination and reveal private health information just to go about their daily lives."
At the beginning of April, Florida Gov. Ron DeSantis rolled out an order prohibiting the state from issuing vaccine passports or evidence of immunization.
"Today I issued an executive order prohibiting the use of so-called COVID-19 vaccine passports," DeSantis, a Republican, said in a tweet. "The Legislature is working on making permanent these protections for Floridians and I look forward to signing them into law soon."
In the order, DeSantis said that such records are private information, "which should not be shared by mandate," and that "vaccine passports reduce individual freedom and will harm patient privacy."
The ban prevents businesses from requiring customers to show verification of Covid-19 vaccination or post-transmission recovery.