WASHINGTON (BLOOMBERG) - Covid-19 vaccination requirements are fast becoming facts of life in the US, spreading business by business even as politicians and privacy advocates rail against them.
Brown, Notre Dame and Rutgers are among universities warning students and staff they'll need shots in order to return to campus this fall.
Some sports teams are demanding proof of vaccination or a negative test from fans as arenas reopen. Want to see your favourite band play indoors in California? At bigger venues, the same rules apply.
A Houston hospital chain recently ordered its 26,000 employees to get vaccinated.
Yet it's another matter how people prove they've had their shots or are Covid-free.
Republican politicians and privacy advocates are bristling over so-called vaccination passports, with some states moving to restrict their use.
Given the fraught politics, many companies are "not necessarily wanting to be the first in their sector to take the plunge", said Dr Carmel Shachar, executive director of the Petrie-Flom Centre for Health Law Policy, Biotechnology and Bioethics at Harvard Law School.
Still, "we're going to see employers start to require vaccinations if you want to come into the office, if you will have a public-facing job".
While there may be an uptick in companies asking whether they can require vaccinations, few are ready to make that commitment.
The Biden administration is leaving the issue to the private sector, with White House Press Secretary Jen Psaki this week saying the US government won't issue vaccine passports.
They are usually conceived of as smartphone apps that show the holder has been immunised against Covid, eliminating the need to carry around the paper card that comes with completed vaccinations.
"It would be a simple check for employers to do," said Ms Susan Kline, an employment lawyer in Indianapolis.
"But when you start looking at saying everyone has to show their passport, there starts to be a lot of obstacles."
The stipulations are following the same haphazard pattern that has characterised so much of the US pandemic response, varying company by company, state by state, and subject to the vagaries of local politics.
But it is clear that vaccination rules will become a continuing concern for anyone who works in a US business or patronises one.
Public health measures became a partisan issue as soon as former President Donald Trump began downplaying the pandemic and fierce debate arose over its severity, the wearing of masks and government-enforced lockdowns.
Vaccine requirements and passports have become the latest flash points.
"Idahoans should be given the choice to receive the vaccine. We should not violate Idahoans' personal freedoms by requiring them to receive it," said Idaho's Republican Governor Brad Little on Wednesday (April 7) after signing an executive order banning the vaccination requirement for people seeking public services.
The governors of Florida and Texas have issued similar orders.
"Vaccine passports create different classes of citizens," Mr Little said.
And yet, New York state has unveiled its "Excelsior Pass" smartphone app to quickly prove vaccination or a clean test.
The widely used Clear airport check-in system will soon offer its own version.
Many businesses have, so far, decided on a lighter touch.
As they reopen offices, they have strongly encouraged employees to get vaccinated but stopped short of requiring it.
That includes Amazon, which offers front-line employees as much as US$80 (S$107.32) to be immunised, and Walmart, which provides shots at its stores and gives associates two hours of paid time off to get theirs.
A recent survey by the consulting firm Mercer Total Health Management found that 73 per cent of employers don't plan to make vaccination a requirement.
"People don't want to go into something that feels like an antagonistic relationship in their workforce," said Ms Mary Kay O'Neill, senior clinical adviser for Mercer.
"Employers are just trying to be supportive and facilitative of getting the vaccine without it being a rule."
The Houston Methodist healthcare system is taking another tack.
Its chief executive officer, in a March e-mail, gave managers until mid-April to get their first dose, or an exemption. He didn't specify a deadline for other employees.
"Thank you for getting vaccinated and thank you for leading your staff to make the right decision to help protect our patients," wrote Chief Executive Officer Marc Boom.
Rules are proliferating, even in workers' leisure time.
The Boston Marathon may require runners to produce two negative Covid tests for its October event.
"Official entrants will receive more information in the coming months on testing timelines and requirements," the Boston Athletic Association warned.
Civil liberties advocates worry about the privacy implications of any passport system.
Mr Alexander Howard, a Washington-based information privacy expert and director of the Digital Democracy Project, said such phone apps could lead to personal information landing in government or private databases via stadium entrances, airport boarding gates or anywhere the devices are swiped.
"We've got a supercomputer in our pocket that gives us godlike powers but that can also be used against us," he said.
Yet some who've had their shots see a benefit in being able to quickly prove it.
Mr Julio Elizalde, a 36-year-old concert pianist from the San Francisco Bay area, said a vaccine passport would make his life so much easier - and less expensive - starting in June, when he has a performance in Taipei.
He must arrive three weeks in advance for quarantine, he said, and is trying to book a hotel or a private home that can equip him with a baby grand piano so he can practice.
"I'm actually fully vaccinated," Mr Elizalde said. "I wish I could prove that I had my two shots."
Some legal experts have cautioned that because vaccines have only emergency federal approval, businesses can't require them.
But that issue is "a bit of a red herring", Harvard's Dr Shachar said, because the vaccine data is so strong, the shots are so effective and the virus is so dangerous.
Many universities already require student vaccinations for other diseases.
They say they're on firm footing to mandate coronavirus vaccines, said Ms Emily Morgese, a vice-president of the Commission on Independent Colleges and Universities in New York, a group for administrators.
Implementation, however, can be tricky, particularly for schools with large international populations.
"If a college requires a vaccine, but students are coming from countries that are utilising vaccines not approved by the FDA, how does that work?" Ms Morgese said.
For some, their approach is dictated by the states in which they operate.
The Mets and the Yankees, for example, didn't decide that their fans would need proof of vaccination or a negative test to attend a Major League Baseball game - New York state did.
It's the same with California concert venues that are finally being allowed to reopen.
On Friday, the San Francisco Giants played their home opener under similar restrictions, requiring proof of vaccination or a negative Covid test within 72 hours of the game.
The team's chief executive officer, Mr Larry Baer, told local television station KTVU that the restrictions would help fans feel comfortable as they return to Oracle Park.
"We will have the safest spot on Planet Earth," he said. "When you're coming to a game, you know you're going to be safe - you'll feel good."