More than two-dozen travel industry groups and labor unions on Monday urged the Biden administration to issue guidelines for a standard coronavirus vaccine passport, hoping to boost both domestic and international travel as the nation's vaccine roll-out continues.

In a letter to Jeffrey Zients, the head of the White House's COVID-19 recovery team, airline industry groups called for the United States to set the standard for vaccine passports as efforts for some kind of COVID-19 Health Credentials, or CHC, are underway in other regions.

"The currency diverse and fragmented digital health credentials used to implement different countries' air travel testing requirements risk causing confusion, reducing compliance and increasing fraud," the travel groups wrote, quoted by Bloomberg News.

Currently, international air travel industry has been severely depressed when compared to pre-pandemic levels due to travel restrictions and other public health and safety policies like mandatory testing and quarantine periods. In an effort to safely reopen borders--without the threat of another wave of COVID infections--governments need to be confident that travellers are not going to bring the virus in with them. This means that having accurate testing and vaccine data is a must for the international air travel industry to recover back to pre-pandemic passenger levels.

"The Centers for Disease Control and Prevention (C.D.C.) can help the global discussion, increasing certainty that test results are legitimate, prioritizing passenger privacy, improving operational efficiency for the aviation industry ecosystem, and strengthening protections against importation of the virus," the letter added.

A vaccine passport can also eventually be used for attendees in other public spaces like stadiums and theme parks, as well as business meetings and workplaces, the letter stated, which was signed by 27 industry members in total, including the Air Traffic Control Association, the Global Business Travel Association, Airports Council International-North America, the Allied Pilots Association and the Association of Flight Attendants-CWA, according to Bloomberg.

A vaccine passport will give travellers a way to share their tests and vaccination results in a way that it both verifiable and privacy-protecting, which can give governments more confidence to open borders, according to the International Air Transport Association (IATA).

Recently, the IATA launched a Travel Pass initiative that aims to solve the issues surrounding passengers having accurate health information for international travel by providing a standardized global solution that includes COVID test verification or vaccine certificates. Multiple airlines are trialing the IATA Travel Pass, including the International Airlines Group (ICAGY  ) and Qantas (QUBSF  ).

At this time, the C.D.C. discourages both domestic and international travel, even for those that have been fully vaccinated against the virus due to the nation's elevated daily infection and hospitalization rates.