Vaccine passports could become available soon to help people resume their lives — but theyface numerous scientific, social and political barriers to being accepted.

The big picture: Reliable and accessible proof of vaccine-induced protection from the novel coronavirus could speed international travel and economic reopening, but obstacles to its wide-scale adoption are so great it may never fully arrive.

Driving the news: The secure digital identity app CLEAR and CommonPass, a health app that lets users access vaccination records and COVID-19 test results, will be working together to offer a vaccine passport service, my Axios colleague Erica Pandey reports.

• The news comes as a growing number of countries and companies are talking up plans to introduce similar vaccine passports that could help the protected return to normal life and travel as soon as possible.
• "To restart the economy, to save certain industries, I think you need a solution like this," Eric Piscini, a vice president at IBM who oversaw the development of the company's new health passport app, told the New York Times.

Yes, but: There are numerous health, ethical and operational questions that need to be resolved before vaccine passports could become an effective part of daily life.

Health: Medical experts still don't fully know how effective vaccinations — or exposure to the virus — are at preventing onward transmission of COVID-19.

• While the CDC is set to soon release new guidance around social activity for fully vaccinated people, current recommendations still call for them to keep wearing masks and practicing social distancing.
• Until it's clear that vaccination effectively prevents transmission, there's a limit to how useful any vaccine passport can be for public health — especially if emerging variants render some vaccines less protective.
• “The utility of a vaccine passport is only as good as the evidence of how long the immunity lasts,” David Salisbury, an associate fellow at think tank Chatham House, told Bloomberg. “You could find yourself with a stamp in your passport that lasts longer than the antibodies in your blood.”

Ethical: The most obvious use case for vaccine passports is for international travel, which has been crippled by onerous quarantine restrictions. But such a system risks locking out billions of people who are unable or unwilling to get the vaccine.

• The EU has been discussing the creation of a vaccine passport, with tourism-dependent countries like Greece leading the charge. But Germany and France — where the vaccine rollout has been low and hesitancy is high — have reservations, and any such system looks to be months away.
• A bigger ethical concern is the many people in developing countries who may not get access to vaccines of any sort for months or even years while rich nations hoard supplies.
• And if vaccine passports are used not just for international travel but to allow people to work and engage in social life domestically, they could create cripplingly unequal barriers that might paradoxically reinforce vaccine hesitancy.

Operational: Passports for international travel are regulated by governments and have decades of history behind them, but there's no such unified system for vaccine passports, which are being introduced by governments and businesses with different standards, making them a target for fraud.

• The U.S. in particular has a decentralized medical system that can make it difficult for people to easily access their health care records, especially if they lack digital literacy.
• "I can pretty much 100% guarantee that fraud is going to occur," says Jane Lee, a trust and safety architect at the cybersecurity company Sift. "We will have a lot of bad actors where they pretend to offer a service that will provide some sort of vaccination passport, but it's really a phishing campaign."

Be smart: None of these obstacles are insurmountable on their own. But as we saw with the failures of digital contact tracing, just because a technological solution exists doesn't mean it will be effective or adopted by the public.

• "There's a huge motivation to make this work socially," says Kevin Trilli, chief product officer at Onfido, an identification verification company. "But there's a lot of governmental issues that are going to really make the system difficult to implement."
• There's a time pressure at work here as well, especially in the U.S, where vaccination rates have picked up. The more people who are vaccinated, the less value there will be in creating a complex system to sift the protected from the unprotected.

The bottom line: Some form of vaccine visas will likely be introduced for international travel, but it seems unlikely they'll become a passport to resuming normal life.