The World Health Organization (WHO) said on Friday it was opposed "for the time being" to the introduction of certificates of vaccination — so-called "vaccine passports" — against COVID-19 as a condition for allowing international travellers entry into other countries.
Several countries have already signalled their interest in producing vaccine passports in some form, including Spain, Belgium, Iceland, Estonia, and Denmark.
"There are still too many fundamental unknowns in terms of the effectiveness of vaccines in reducing (virus) transmission and vaccines are still only available in limited quantities," the committee said in its recommendations, adding that proof of vaccination should not exempt from other health precautionary measures.
Poland became the latest European country to announce the introduction of vaccine passports on Thursday.
The country's deputy health minister Anna Goławska said Poles would be able to access certification in the form of a downloadable QR code after they received the second dose of a coronavirus vaccine. The code would then allow the recipient to "use the rights to which vaccinated people are entitled".
Last week, Denmark said it would look at the development of a vaccine certificate in order to ease restrictions on travel and freedom of movement.
The ethics of vaccine passports has been the subject of debate, with the UK's University of Exeter recently publishing a study on their impact on human rights.
"Digital health passports may contribute to the long-term management of the COVID-19 pandemic. However, they pose essential questions for the protection of data privacy and human rights," Ana Beduschi, an associate law professor and one of the report's authors, told Euronews.
She added that the requirement to show your health records in order to access public and private spaces would serve to marginalise people and restrict their freedom.
"Arguably, such measures could preserve the freedoms of those who do not have the disease or have been vaccinated," Beduschi said. "However, if some people cannot access or afford COVID-19 tests or vaccines, they will not be able to prove their health status, and thus their freedoms will be de facto restricted".
Wojciech Wiewiórowski, the EU's Data Protection Supervisor, has similarly raised concerns over "immunity passports" in the past, calling them "extreme" and "based on assumptions not confirmed by medicine".
At the same WHO press conference on Friday, the agency's chief executive officer Tedros Adhanom Ghebreyesus called for vaccination campaigns against COVID-19 to begin in all countries of the world within the next 100 days.
"I want to see vaccination started in all countries within the next 100 days so that health workers and those at high risk are protected first," he said at a press briefing in Geneva.
So far, vaccination campaigns have started almost exclusively in richer countries.