As the pace of vaccination accelerates, governments, corporations and schools have signalled support for so-called vaccine passports - standardised proof of inoculation.
But in the US, the idea has been met with swift resistance.
"The government is not now nor will we be supporting a system that requires Americans to carry a credential," said White House press secretary Jen Psaki on Tuesday.
While mask mandates quickly became fodder for the culture wars, there's resistance to vaccine passports from all sides. Conservative leaders say they will resist any movement toward a vaccine pass, arguing it's an infringement of individual freedoms.
Some progressives, too, have raised concerns, saying vaccine passport schemes are likely to exacerbate existing inequality.
Experts say the resistance is a product of America's peculiar public health history.
"This is not a country that has necessarily deep heritage belief in government or in science," said David Rosner, a socio-medical sciences professor at Columbia University. "The idea of having ID cards or green passes here, I think it's going to create another giant political crisis."
Two centuries before the coronavirus reached the US, yellow fever ravaged America's Deep South - states like Georgia, Louisiana and Mississippi.
In New Orleans - then the region's social and cultural hub - the mosquito-borne virus was a near-constant source of fear. Between 1800 and 1860, the city experienced 22 epidemics, killing some 150,000 people.
"This was a petrifying disease," said Kathryn Meyer Olivarius, a professor of history at Stanford University who specialises in 19th century America.
It was made worse because the disease was so misunderstood.
"There was no cure, there was no inoculation, they did not understand that it was bred by mosquitoes," Prof Olivarius said.
Over time, it became clear that surviving yellow fever meant immunity from future infection.
Within a society that enslaved thousands of people at the time, another hierarchy emerged.
White residents who had developed immunity - who had "acclimated" - sat at the top, while those who hadn't were denied jobs and life insurance.
"Fathers would not let their daughters marry unacclimated men," Prof Olivarius said.