A panel of scientists has outlined the difficulties of rolling out a vaccination certificate recognised globally as inoculation rates steadily increase around the world.

Speaking during World Travel & Tourism Council/ Carnival Corporation Global Science Summit on Thursday, US-based scientists – Dr Michael Lin; Dr Jewel Mullen and Dr Clare Rock – raised concerns about certificates.

More than 37% of Americans eligible for a vaccination have now received at least one dose, according to latest data, which also showed Israel (61%) and the UK (47%) have immunised higher proportions of their populations.

Questioned by WTTC president and chief executive Gloria Guevara about the prospect of vaccine certificates, Lin said: “I don’t think they would be worth it. We don’t have universal system in the US, everyone’s records are protected and not linked to a national database it is exceedingly difficult for people to provide or obtain vaccine information.”

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He added that the process of sharing such information would be on “a voluntary basis” in countries like the US where there is no national health service.

“The situation is different in other countries which have national health services,” he said, adding that in such countries: “People are more receptive of government regulations.”

Lin said he supported the idea of vaccination certificates – despite the issues he raised.

“If we could prove that we’re vaccinated which would give us access to a concert, to a restaurant or a [cruise] ship that would be great,” he said, but noted: “Opinions differ on this matter – especially in the United States.”

Mullen said vaccination certificates were “easier to talk about than to implement”, adding that they were “not practical”.

“In a society where people have freedoms, we’re still trying to encourage people to make the best public health decisions for themselves,” she said. “I cannot answer that question from a domestic perspective because we’re part of a global community.

“There are countries where not even 1% of the population has been vaccinated. That’s where I want us to redouble our efforts now as we talk about mobility and societal protection.

“With a [vaccination] passport, that allows people to travel globally, I hope people remember that the places they go as visitors are places where people call home. So what those individuals need is a concern for all of us.”

Rock said the issue of vaccine certificates is “challenging”, adding: “The question is, will private third-party companies be able to validate those pieces of paper or cards that are given to people in order to certify that the vaccination process has happened?”

Arnold Donald, Carnival Corporation’s president and chief executive, concluded the summit by saying that its purpose was “to focus on science rather than talk about global travel or cruise” during the pandemic.