A year ago, vaccines to tackle the covid pandemic seemed like a far-off idea. Today, though, doses have been delivered to almost one-quarter of the world’s people—and some are being asked to prove they’re among them, leading to the rise of so-called vaccine passports. The details of these credentials vary from place to place, but at their heart they are the same: digital health records, stored on your phone, to use as proof that you are a low risk to others.

Supporters of digital vaccination credentials say the benefits are clear: they make congregating less risky while incentivizing vaccinations. But critics see drawbacks and disadvantages. They say introducing vaccine passports infringes on civil liberties, unfairly punishes those who cannot get vaccinated (and discriminates against those who will not), unleashes another form of surveillance, and worsens inequalities rather than eradicating them. 

Faced with this divergence of views, governments are taking very different approaches. In Europe, for example, seven countries launched a “digital green certificate” at the beginning of June, with another 21 nations due to join shortly. But some places are taking the opposite stance, strictly limiting the use of such documents or even banning their development altogether.

Along with these debates, there is still basic confusion about how systems would be used. Some, like the EU’s app, are for traveling between nations. Others, like New York State’s, are for getting into everyday places like restaurants and events. The term “passport” itself is becoming more ambiguous and simultaneously more loaded: when California governor Gavin Newsom announced the launch of his state’s digital certificate, he specifically stated, “It’s not a passport; it’s not a requirement.”

Recent precedents

Controversy around new technologies has been a running theme during the pandemic. But while some—like the vaccines themselves—have encouraged conspiracy theories, a more useful parallel may be digital contact tracing apps—systems intended to let you know if you’d been exposed to the virus. These started blanketing the world last spring as public health officials and technologists tried everything they could do to stop the spread. 

We started tracking the use of digital contact tracing apps last May. Since then, our tracker has been viewed tens of thousands of times and has been cited in hundreds of research papers. But despite the attention these apps have received, our recent analysis shows that exposure notification systems missed their moment, at least in the US. 

So will this latest form of covid tech be more effective? What’s really happening with digital vaccination credentials? We’re researching what various places are developing, starting with US states.

What’s happening with vaccine passports in the US

President Joe Biden has already said there won’t be a national app, leaving the choice to states. Some states have banned the apps outright as examples of government overreach. Often the debate over the technology seems like a proxy for a larger question: Should governments and businesses be allowed to require vaccination for covid? We looked at the status of digital vaccine systems in all 50 states.

A few key takeaways:

• Most states have addressed the technology in some way, either in legislation or in comments from a lawmaker, a public health official, or the governor.
• 4 states have active vaccine certification apps.
• 19 states have banned the systems to some degree, typically through executive orders. Most, though not all, of these states are Republican-led. 
• Some states have banned their use only in facilities or agencies connected to state government; others have enacted moratoriums on any use whatsoever. 

• Alabama: Governor Kay Ivey signed legislation to ban vaccine passports. The Alabama House of Representatives voted 76–16 to approve the bill. (Source: AP News)
• Alaska: Governor Mike Dunleavy issued Administrative Order No. 321, stating that Alaska’s government will not require vaccine passports in order to travel to, or around, the state. (Source: Alaska State Website)
• Arizona: Governor Doug Ducey issued an executive order banning vaccine passports on April 19 (Source: AZ Governor website), but on May 22, Arizona lawmakers failed to pass a bill banning businesses from requiring vaccine passports. The measure, House Bill 2190, would have prohibited businesses or third-party online entities from asking “whether the person has or has not received a COVID-19 vaccine or a vaccine to address any variant of COVID-19 as a condition for receiving any service, product or admission to an event or venue.” (Source: The Hill) 
• Arkansas: Governor Asa Hutchinson signed a law that prevents state and local governments from requiring covid-19 vaccine or proof of vaccination in order to access services. The state’s majority-Republican senate voted 23–8 to ban vaccine passports. (Source: ABC Little Rock)
• California: Residents can verify their vaccinations using a service called the Digital Covid-19 Vaccine Record portal, which launched on June 18. (Source: NBC) The state does not require an official vaccine passport, but does mandate that indoor events with at least 5,000 people require vaccination or a negative covid test. Organizers of outdoor events with more than 10,000 people will be encouraged, but not required, to check for vaccination or a negative test, or to require masking. (Source: The Daily Democrat)
• Colorado: Vaccine passports are not required in Colorado, but state health department officials said in early April that they will at least explore the possibility. (Source: U.S. News/AP)
• Connecticut: There is no state program for vaccine passports, but in March Governor Ned Lamont maintained that they could be introduced in Connecticut through the private sector. (Source: CT Post) 
• Delaware: Governor John Carney said in a statement that “we’re not going to be in the business of asking people for a so-called vaccine passport.” (Source: WHYY)
• Florida: Governor Ron DeSantis signed Senate Bill 2006, effectively banning vaccine passports, blocking any business or government entity from requiring proof of covid-19 vaccination. (Source: FL Governor website)
• Georgia: Governor Brian Kemp issued an executive order May 25 prohibiting vaccine passports in state government. No vaccine passport will be required for entry into the state of Georgia. State employers cannot have different rules for employees based on vaccination status, unless such rules are implemented using an honor system and no proof of vaccination is required. (Source: GA Governor website)
• Hawaii: The “Safe Travels Card” appears to be the official moniker for the Hawaii vaccine passport, which is being tested among residents. Travelers will likely use the system for vaccine verification from July 8. (Source: Hawaii Travel Guide)
• Idaho: Governor Brad Little issued an executive order on April 7 banning the state government from requiring or issuing vaccine passports. (Source: US News/AP)
• Illinois: No vaccine passport is established currently, but Illinois Department of Public Health officials have said that they are “working to provide this service to individuals.” Public health commissioner Allison Arwady said that the “Vax Pass” will be required to attend concerts and other summer events. (Source: Illinois Policy)
• Indiana: Lawmakers passed a ban on vaccine passports on April 22. The legislation, HB 1405, forbids the state or local governments from issuing or requiring the documents. (Source: WFYI Indianapolis) 
• Iowa: On May 20 Governor Kim Reynolds signed a law, House File 889, that will withhold state grants and contracts from local governments or businesses that require customers to prove they have received a covid vaccine. The law also prevents state and local governments from including a person’s vaccination status on a government-issued identification card. (Source: Des Moines Register)
• Kansas: On May 7, lawmakers approved a proposal that includes a ban on vaccine passports, but it has not yet been implemented. Governor Laura Kelly said in April that she has no interest in any state-sanctioned use of the technology. (Source: The Topeka Capital-Journal) 
• Kentucky: Vaccine passports are not required, and State Representative Brandon Reed is drafting a bill that would ban the government from enforcing their use. (Source: NBC KY News) 
• Louisiana: Residents will be able to show digital proof of vaccination via the LA Wallet mobile app, the state’s voluntary license application, as of May 5 (Source: AP News). On June 7, the Louisiana Senate voted 23–12 for state representative Danny McCormick’s House Bill 103, which prevents civil liability for businesses that don’t mandate vaccines and also prevents the state from denying business licenses to those that don’t require a shot. (Source: Lafayette Daily Advertiser) 
• Maine: Officials are not planning on developing a statewide vaccine passport system. Residents are encouraged to bring their immunization record card if they need it. (Source: AP News); 
• Maryland: Vaccine passports are not required, and there is no legislation addressing passports as of now. The biotechnical distribution company MyBioSource.Com surveyed 3,000 Marylanders and found that overall, 63% believe vaccine passports should be used. (Source: CBS Baltimore) 
• Massachusetts: Governor Charlie Baker said on April 8 that he is opposed to vaccine passports, but no ban has been passed. (Source: Boston Globe) 
• Michigan: The state house of representatives passed a bill, HB 4667, on June 2 to ban vaccine passports or any other system where individuals’ civil rights are diminished by vaccine status. (Source: US News) 
• Minnesota: The state senate passed S1589-2 in May, stating that no person must be required to possess, wear, or display any indicator that he or she “received a negative or positive test result or possesses the antibodies for a communicable disease.” The Minnesota Department of Health is prohibited from forcing anyone to participate in contact tracing or digital contact tracing. (Source: Minnesota State Republican Caucus website)
• Mississippi: Governor Tate Reeves said in April that he doesn’t support vaccine passports, and the state is not pursuing the use of one. (Source: CNN) 
• Missouri: In May the state house and senate approved provisions to HB271, a bill that aims to ban vaccine passports. The bill has not yet been approved or vetoed by Governor Mike Parson. (Source: The Kansas City Star) 
• Montana: Governor Greg Gianforte issued an executive order prohibiting state-sponsored development of vaccine passports or requirements for their use. (Source: Montana State website) 
• Nebraska: Governor Pete Ricketts issued a statement on March 13 saying that the state will not participate in the vaccine passport program. (Source: Nebraska Government website)
• Nevada: Vaccine passports are not actively banned, but they are not required within the state. US Senator Jacky Rosen said on May 4 that she does not support requiring vaccine passports for local events. (Source: Las Vegas Review-Journal)
• New Hampshire: State representative Tim Baxter proposed a legislative measure on April 28 looking to bar the required use of passports. The state is currently not developing or requiring them. (Source: NHPR)
• New Jersey: The state has no plans to implement a vaccine passport system. Governor Phil Murphy has said he’s open to the idea but that the state will follow federal guidance. (Source: Philly Inquirer). On May 6, Assemblyman Gerry Scharfenberger introduced bill A5607 to prevent the use of vaccine passports. (Source: Inside NJ)
• New Mexico: There are no requirements for vaccine passports and no plans to develop one.
• New York: The state has implemented a vaccine passport system, the Excelsior Pass, created by IBM. Vaccine status can be stored digitally on an app, available on the App Store and Google Play store, and can be printed out on the Excelsior Pass website to be brought anywhere. Available languages are English, Spanish, Chinese, Russian, Haitian Creole, Korean, Bengali, Arabic, Italian, Polish, and Yiddish. (Source: NY State website)
• North Carolina: On April 21 the state house of representatives urged Governor Roy Cooper to reject attempts to create a vaccine passport system, with 65 Republican lawmakers sending a letter of opposition. Passports are not required in the state. (Source: WCNC Charlotte) 
• North Dakota: Lawmakers passed a limited ban on vaccine passports, and amended the ban into HB1465 on April 29. The law bans state and local governments from requiring proof documents and prohibits businesses—with some exceptions—from requiring customers to present vaccination documents for access, entry, or services. The legislature also passed a resolution, SCR4016, urging Congress to refrain from issuing a vaccine passport. (Source: The Bismarck Tribune)
• Ohio: Governor Mike DeWine made a commitment that the state will not create or require a vaccine passport, but he has left the issue of private-sector requirements up to individual businesses. The state house of representatives introduced bill HB248 to ban mandatory vaccinations and the use of vaccine passports. (Source: ABC6 Ohio)
• Oklahoma: Governor Kevin Stitt issued an executive order on May 28 banning state agencies from requiring vaccinations as a condition of entry to public buildings. He also signed SB658, which prohibits schools from requiring covid vaccinations for K–12 students or implementing mask mandates that would apply only to unvaccinated students. (Source: The Oklahoman) 
• Oregon: Vaccine passports are not required. On June 3 state senator Kim Thatcher introduced a bill that would ban any kind of vaccine passport (Source: ABC2 KATU); the Department of Consumer and Business Services said in a May 19 statement that “an employer who requests and reviews verification of vaccination may permit fully vaccinated individuals with such proof to go without masks, face coverings, etc.” 
• Pennsylvania: On May 24, Republicans in the state senate began advancing legislation to prohibit government and school districts from requiring vaccination. The bill applies to state agencies, counties, municipalities and school districts, and bars; it does not apply to private businesses or organizations. (Source: AP News)
• Rhode Island: Governor Dan McKee said on May 18 that he is leaving it to business owners and employers to decide rules on masking and vaccination for themselves. McKee is not in support of a bill introduced by Republican lawmakers that would prohibit state and municipal agencies and private business from requiring proof of vaccination. (Source: The Providence Journal) 
• South Carolina: Governor Henry McMaster issued an executive order on May 11 that prevents local governments and schools from creating mask mandates. The order also bans local governments, state agencies, and state employees from requiring vaccine credentials. (Source: WebMD)
• South Dakota: Governor Kristi Noem issued an executive order on April 21 banning the development or use of vaccine passports. (Source AP News)
• Tennessee: The state senate passed a ban on vaccine passports with SB0858 on April 14; Governor Bill Lee said in April on Twitter that he “opposes vaccine passports,” adding, “The COVID-19 vaccine should be a personal health choice, not a government requirement.” (Source: The Hill)
• Texas: On June 7 Governor Greg Abbot signed bill SB968, which bans businesses from requiring proof of the vaccine; vaccine passports are prohibited in the state. (Source: Texas Tribune) 
• Utah: A law passed in April, HB308, blocks state government from requiring people to get vaccinated. (Source: Salt Lake Tribune); Governor Spencer Cox confirmed that vaccine passports will not be used in the state. (Source: CBS Local KUTV)
• Vermont: The state house of representatives introduced a bill, H452, to ban vaccine passports on May 20. (Source: Vermont Daily Chronicle) 
• Virginia: Governor Ralph Northam has not ruled out vaccine passports as a condition for entry into certain places—but in May he said his administration has no plans to use them in the state. (Source: Wavy.Com)
• Washington: State representative Jim Walsh introduced a bill on April 7 prohibiting vaccine passports. (Source: Washington State House of Representatives website)
• West Virginia: Vaccine passports are not required, but Governor Jim Justice has not prohibited proof-of-vaccination requirements at any level of government. (Source: Ballotpedia) 
• Wisconsin: Requirements for vaccine credentials are not actively banned, but in April a series of bills were introduced to do so. (Source: CBS Milwaukee)
• Wyoming: Governor Mark Gordon issued a directive on May 7 preventing state agencies, boards, and commissions from requiring people to show vaccine status to access state spaces or services (Source: Oil City News); state representative Chuck Gray said on June 8 that he is drafting a bill to officially ban vaccine passports in the state. (Source: Oil City News)

What’s next

While governments take their own approaches, private ventures are launching too. Workplaces, transportation providers, schools, and venues are among those looking at how to prove vaccination—with some even developing the technology themselves. We will be documenting the use of these technologies in private and public spaces, by organizations big and small. 

If you have information on how in your city, state, or country is using vaccine certification, or if you know of unusual uses of covid status apps, please help us keep our list up to date by emailing ctt@technologyreview.com. We can’t promise to reply to every email, but we will be regularly updating our lists as new information comes to light.

This story is part of the Pandemic Technology Project, supported by the Rockefeller Foundation.