One year ago, it seemed impossible to find vaccines that could combat the covid pandemic. Today, however, vaccines have been administered to nearly one-quarter the population. Some are now being asked to prove their eligibility, leading to so-called vaccine passports. These credentials may vary in details depending on where they are located, but the core of them are the same: digital records that are stored on your smartphone and used to prove you are low-risk to others.Digital vaccination credentials supporters claim that they have clear benefits. They make it less risky to gather and incentivize vaccinations. Critics see both drawbacks as well as disadvantages. Critics claim that vaccine passports violate civil liberties and unfairly punish those who are unable to get vaccinated.Governments are taking different approaches to this divergence. Seven European countries, for instance, launched a digital green certification at the start of June. 21 more nations are expected to follow suit. Some countries, however, are restricting the use of these documents or banning their creation altogether.These debates are not the only ones. There is also some confusion over how systems will be used. Some systems, such as the EUs app for mobile travel between countries, can be used to do this. Some, such as the New York States app, allow for entry to everyday places, such as restaurants and events. The concept of passport is becoming more complicated and more loaded. When Gavin Newsom, the governor of California, announced the launch his digital certificate for his state, he stated that it was not a passport, but a requirement.Recent precedentsThe pandemic has seen controversy surrounding new technologies as a constant theme. While some vaccines have encouraged conspiracy theories, others like digital contact tracing applicationssystems that can help you determine if you've been infected with the virus may offer a better parallel. They began to spread around the globe last spring, as technologists and public health officials tried their best to stop it.Last May, we began tracking digital contact tracing applications. Our tracker has been viewed thousands of times since then and has been cited hundreds of times in research papers. Our recent analysis shows that, despite all the attention these apps have received from the public, exposure notification systems are still not the right time for them, at least in the US.This latest covid tech will be more efficient? What is the real story with digital vaccine credentials? We are looking at what is happening in different places, starting with the US.What's the status of vaccine passports in the US?Joe Biden, President of the United States, has stated that there will not be a national app and that it is up to each state to decide. As an example of government overreach, some states have outright banned these apps. The debate about the technology is often seen as a proxy for a bigger question: Should governments or businesses be allowed covid vaccinations? We examined the current status of all 50 state's digital vaccine systems.Here are some key points to remember:The technology has been addressed in legislation by most states.There are 4 states with active vaccine certification applications.19 states have implemented executive orders that ban the system to some extent in at least one state. These states are overwhelmingly Republican-led, although not all.Some states prohibit their use in agencies or facilities that are connected to the state government, while others have placed moratoriums on all use.Next stepsPrivate ventures are also being launched, while governments continue to take their own approach. Many people are looking for ways to prove vaccination. Some even develop the technology themselves. These technologies will be documented in public and private spaces by large and small organizations.Please email ctt@technologyreview.com if you have any information about vaccine certification in your country, city, or state. Also, please let us know if there are unusual uses for covid status apps. While we cannot guarantee to answer every email, we will keep our lists updated with new information as it becomes available.This story is part the Pandemic Technology Project, which is supported by Rockefeller Foundation.