They could be our ticket to travel freedom, and the key for cities to revive struggling economies.
More and more destinations are flagging the potential introduction of health passports that would ensure tourists are virus-free when border lockdowns lift and travelling resumes.
The travel documents would be used in tandem with existing passports to prove tourists and other travellers aren't bringing the virus with them.
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The popular Italian island of Sardinia, where the pandemic has crippled the local tourism industry, is keen to introduce them in time for the northern summer.
Under Sardinia's plan, visiting tourists would have to present their health credentials and have their temperatures checked before they can enter.
"This way we hope to relaunch our tourism sector in June," the island's governor, Christian Solinas, told Arab News.
"Whoever boards a plane or a ferry will have to show (the health passport) along with their boarding pass and their identity document.
"I am sure that it will work fine: we will preserve health and save our economy at the same time. Now everything has to be done to boost tourism. It is the biggest source of income for Sardinia."
Italy, which derives about 15 per cent of its gross domestic product from tourism, has been one of the countries hardest hit by Covid-19, mainly in the north.
Other Italian island destinations, such as Capri, Ischia and Panarea, and the southern coastal region of Pulgia, are all considering similar measures.
Greece is also looking at the introduction of health passports, that provide "proof that travellers are not suffering from Covid-19," the country's tourism minister Harry Theocharis told Forbes.
"Negotiations are underway," Greece's minister of state Giorgos Gerapetritis told local radio, according to The Sun. "Visitors will come with some sort of certificate. We are going to try to reduce any possibility of the virus spreading."
Spain's Balearic Islands says a proposed electronic health passport could record relevant details including whether or not a person has already tested positive or negative for COVID-19 to assess their risk of bringing it to the islands.
The European Union is mulling a "Covid-19 passport" to be used by European travellers across the union. Turkey has also discussed the possibility of health passports, as well as Chile, which wants to be the first country in the world to introduce "clearance passports" to its citizens.
While the health passports being considered in Italy and Spain will ensure a traveller is not unwell at the time of arrival, Chile's passports will go a step further by declaring a person has been infected and recovered, and therefore "posed no risk" of further transmission.
They are also not for travellers but for citizens and could be the key to getting people back to work.
Chile says the proposed document is not an "immunity passport" but that those who have already been infected will be key to rebooting the economy.
"One of the things we know is that a person who has … lived through the disease is less likely to become ill again," Paula Daza, sub-secretary of Chile's Health Ministry, said last week, Reuters reported.
Australia's Prime Minister Scott Morrison has said he can't see international travel happening for Aussies "anytime soon" as "the risks there are obvious".
However the Australian government is looking at opening a potential trans-Tasman "bubble" with New Zealand if cases in both countries remain low.
"The only exception to that … is potentially with New Zealand, and we have had some good discussions about that," he said.
The World Health Organisation has warned against countries against issuing "immunity passports", for the simple fact it is not yet clear whether contracting the virus makes people immune, or at lesser risk of a second infection.
"There is currently no evidence that people who have recovered from Covid-19 and have antibodies are protected from a second infection," WHO said, adding false confidence carried the risk of another outbreak.
Temperature checks are not foolproof either, as some people can spread the virus without showing symptoms, while others may have contracted it but be in the incubation period.
Whether countries' plans for health documents proceed, health screening is likely to be a lasting aspect of travel once travelling resumes.
Andrew Charlton, managing director of the consultancy Aviation Advocacy, told the UK's The Times compulsory pre-flight health checks would become the norm – and may even lead to longer airport waiting times.
"Even if it starts raining vaccines tonight, we are still looking at two years at least to get back to levels seen before the outbreak, and it is probably going to be more like five years," he said.
"There will be fewer flights, fewer seats available, prices will go up and there will be very uncomfortable conditions because of the demands to wear personal protective equipment and maintain social distancing.
"Whereas we used to be able to turn up at the airport an hour or two before departure, we could see something as horrible as four hours as health checks are added to the usual palaver of check-in, security and immigration."