Amid doubts and objections about the move, the European Commission this month is set to propose legislation paving the way for EU coronavirus vaccine certificates.
The Digital Green Pass system is expected to be working within three months, possibly as early as summer.
The certificate is set to include data on where a person was vaccinated and with which vaccine, PCR results if they have yet to be vaccinated, and information on whether they have antibodies against COVID-19.
The certificate is meant to make it easier for people to travel within EU member states for business or other purposes.
EU countries such as Spain and Greece, which took great losses last summer due to a lack of tourists, are pushing for the certificates.
Greece has also sought bilateral agreements with non-EU countries and signed a bilateral agreement with Israel on tourism. Athens is also reportedly negotiating with the UK for a similar agreement ahead of this summer.
But the Spanish government wants the measure to be done under the EU umbrella instead of through bilateral agreements.
Airlines and tour operators also stress the need for vaccine certificates for a return to normalcy. The International Air Transport Association (IATA) called on EU leaders to support the vaccine certificate proposal.
Will the passport cause discrimination?
But some countries, such as France, Germany, and Belgium, oppose the vaccine certificate proposal due to worries it might lead to discrimination against people who have not been vaccinated and might raise concerns about fairness.
Opponents also say the certificate could damage the legal foundations of basic rights and freedoms.
Uncertainty about how long the vaccines remain effective and if they prevent the virus from being transmitted are among other concerns about the proposed certificates.
Uncertainty about Russian, Chinese vaccines
One of the challenges for certification is mutual recognition, which requires EU countries to integrate the certificate into their health systems as well as border control systems, using a common database.
Another controversial aspect of the vaccine passport concerns vaccines such as those produced by Russia and China which are not approved by the EU.
EU countries currently use BioNTech-Pfizer, Moderna, and AstraZeneca vaccines, which are approved for use in the bloc. However, Hungary has obtained vaccines from China, as has Slovakia from Russia.
The vaccine passport proposal is also related to how many people will be vaccinated by summer. The EU first aimed to vaccinate 70% of the adult population in member countries by summer, but soon this target was delayed to the end of summer.
To date, only about 7% of the EU population has gotten the COVID-19 vaccine, which caused the bloc to be criticized for the slow vaccine rollouts.