As New Zealand looks forward to kicking off the rollout of Covid-19 vaccines, there's more than better health protection to look forward to.
A coronavirus vaccination in this pandemic world would become a passport to do things you can't at the moment.
It would allow you to jump the various virus hurdles in different countries.
At least for some nations, you will need some form of documentation, to prove you have had the jab, to visit without going through quarantine.
Pandemic passports are becoming more relevant as countries roll out vaccines; accurate, faster tests become available, and coronavirus case numbers drop.
After a horrific holiday period, cases are falling from a high level in North and South America and Europe.
There are still questions over how long immunity lasts, whether vaccinated people can still transmit the virus and if annual shots will be needed. But initial data is promising.
Barring setbacks, the prospect of more normal travel is growing. There will likely be various passes, introduced by different countries. The International Air Transport Association has a health app for travel.
Documentation could be in the form of a card similar to a driver's licence, or on paper with a QR code or via apps on cellphones. It would be - along with pre-flight testing, mask-wearing and in-flight anti-virus measures - part of the travel process for some time.
Economic considerations, with the need to get global travel and tourism back on its feet, will drive the process. At the moment, widespread rates of infection, fear of serious health consequences and border restrictions have crippled travel.
National passports have been the basis for allowing electronic tickets, online check-ins and boarding passes. Covid documentation would need to confirm vaccination and what the person looks like.
For all the talk and promise of travel bubbles, vaccination is the element that would make such arrangements more realistic and durable.
Israel, which has been setting the pace for the world in the speed with which it is vaccinating its population, has reached deals with Greece and Cyprus to open up tourism to the inoculated. Citizens who have certification will be able to soon travel without quarantine.
In Europe, Iceland has been the first to go with documentation. Denmark and Sweden are expected to follow. Vaccine passport projects are in development in Britain, and would likely involve digital certificates verified by the health service and stored on cellphones.
Use of Covid certification could go beyond travel, especially in countries hardest hit.
There's the prospect of employers trying to ensure their workforces are vaccinated. People could potentially be barred from events or specific places without certification. In Britain, cinemas want to use vaccine passports to allow them to reopen their doors to people who have received shots.
Here, because New Zealanders have been able to live normally most of the time, there won't be the same level of pressure. Kiwis are more likely to encounter it elsewhere.
Pandemic passports do raise concerns about fairness and privacy. They could divide people into haves and have-nots.
Vaccinated status means a traveller is less likely to end up in a host country's hospitals. Shots would probably be required for travel insurance.
The people most likely to want to travel offshore for work or holidays - those who are younger and healthier - will be at the back of the queue for shots, at least in this initial rollout.
Vaccine take-up will vary between countries, with some populations more suspicious of both the shots and big tech involvement in pandemic passports.
This is the time for countries to sort through these issues in the hope of wider travel next year.