The Biden administration says there will be no federally mandated system for people to show their Covid-19 status amid fierce debate over vaccine passports as states reopen and travel increases.
"The government is not now nor will we be supporting a system that requires Americans to carry a credential,” White House press secretary Jen Psaki said on Tuesday.
"There will be no federal vaccinations database and no federal mandate requiring everyone to obtain a single vaccination credential."
Dr Anthony Fauci, chief medical adviser to US President Joe Biden, gave a similar opinion to Politico on Monday.
“I doubt that the federal government will be the main mover of a vaccine passport concept,” Dr Fauci said.
“They may be involved in making sure things are done fairly and equitably, but I doubt if the federal government is going to be the leading element of that.”
There are concerns over privacy, protection of medical information and federal involvement when it comes to proving Covid vaccination.
"Americans’ privacy and rights should be protected," Ms Psaki said.
She said the Biden administration would at some point provide official guidance on any Covid vaccination credentials.
It will cover issues of security, privacy and discrimination, Ms Psaki said, so that "these systems are not used against people unfairly".
Private businesses, universities, offices and organisers of large-scale event are debating whether to demand Covid-19 vaccinations and looking at how people can prove they have been immunised.
“There may be theatres that say, ‘You don’t get in unless you have proof of vaccination'," Dr Fauci said.
"There may be colleges or other educational institutions that do that. I’m not saying they should or that they would.
"But I’m saying you could foresee how an independent entity might say, ‘Well, we can’t be dealing with you unless we know you’re vaccinated'."
Legal experts told The New York Times that organisations are allowed to permit or deny entry to people who have not been vaccinated.
The Centres for Disease Control and Prevention already provide cards as proof of inoculation, but other forms of evidence, such as apps, are causing debates over privacy and security.
CommonPass, created by the Commons Project and the World Economic Forum, is an electronic way to show proof of Covid-19 vaccination or a negative PCR test result.
The organisation says the mobile app is in domestic trials.
The International Air Travel Association has a travel pass that is gaining use around the world.
New York state has a similar app called Excelsior Pass, which was developed by IBM.
The state uses it for large-scale events at Madison Square Garden, Barclays Centre and Citi Field, which have reopened with limited capacity.
The application is facing challenges over privacy protection for app users, which have not yet been clarified.
Either way, the state says users can present proof of vaccination or a negative test result without the app.
The debate has become political, with some states moving to ban vaccine passports or credentials.
Texas, which was the first and largest US state to fully reopen, is not allowing vaccine passports.
"As I have said all along, these vaccines are always voluntary and never forced," Governor Gregg 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.”
Florida Governor Ron DeSantis signed an executive order last Friday outlawing businesses from requiring patrons to show vaccine papers.
Mississippi Governor Tate Reeves also said he was against vaccine passports.
The governors of Florida, Mississippi and Texas are all Republican, indicating that the conversation may be divided along party lines.
The prospect of the passports has also become a hot topic on social media, trending high on Twitter in the past few weeks.
People are already required to be vaccinated for some diseases including measles or mumps for international travel.
Proof of vaccination against yellow fever has also been widely referred to in arguments about immunisation cards being used for entry into some countries.
