Instead, the country should carefully consider its risk taking readiness, they add.

Professor Archie Clements, Pro Vice-Chancellor at the Faculty of Health Sciences, Curtin University, Australia, said that "It's not time yet for Vietnam to accept Covid-19 vaccine passports. The country may need to wait a little bit until vaccine coverage gets higher, internationally. Only then can it become a plausible strategy."

Once this happens, Vietnam could consider prioritizing the entry of people from countries with high vaccine coverage or low incidence of the virus, he added.

He noted that existing vaccines only help minimize the risk of transmission. They do not ensure that people are one hundred percent protected from Covid-19.

However, Vietnam may choose to take a risk-based approach in stages, he said. In the early stage, the country might welcome people with vaccine passports from low risk locations like China, Taiwan, Thailand, Laos, Cambodia, New Zealand and Australia.

But one thing Vietnam needs to be sure of before accepting Covid-19 vaccine passports is their credibility, which can be assessed by the quality of governance systems in the countries that issue them, he said.

If the quality of such passports is ensured, people coming to Vietnam should not be asked to undergo the currently mandated 14-day quarantine, "ideally," Clements said.

He stressed that the "no quarantine" allowance should only apply to selected, low-risk countries. People should be required to report their health situation and accept contact tracing, Clements said, adding that he does not support the idea of having a shorter quarantine period for people with the vaccine passports.

Asian preference

Christopher Dye, Professor of Epidemiology, University of Oxford, the U.K., said Vietnam may have a preference for entrants from Asia because they present lower risks. After identifying countries with low rates of infection, Hanoi might welcome tourists and businessmen who have been fully vaccinated.

"It's really a question of using vaccination passports as another instrument and balancing risks at the same time", he said.

Dye said the vaccine passports can be used to replace quarantining, because the latter has become a huge hindrance to international travel.

He noted that in principle, vaccination would be a better method of preventing the import of infections, but only if people were sure about their effectiveness. However, that surety does not exist at present. Information about the vaccine’s efficacy was still being collected.

Dye suggested that Vietnam establishes partnerships with other countries in administering vaccinations and other prevention plans in a manner that facilitates decision-making on the efficacy of vaccines.

He said each country has to keep collecting evidence from around the world in evaluating vaccines.

Harry Severance, Adjunct Assistant Professor, Duke University School of Medicine, the U.S., stressed that if Vietnam were to decide to use a vaccine passport scheme (the country may wish to invoke one of the digital vaccine passport app programs that promise to verify accuracy of the vaccine cards), then quarantining will be a negating factor.

He recommended that instead of quarantine, Vietnam could perform a "point-of-care" antigen screening test on arrival in order to ensure additional safety. In some countries, authorities are requiring visitors to stay at designated participating hotels where they can be better contacted if disease does appear, he noted.

Avoid discrimination

Referring to the domestic implications of vaccine passports, Sharona Hoffman with the Case Western Reserve University School of Law (U.S.) said Vietnam would have to make sure that all residents have access to free vaccines so that the passports do not lead to discrimination and exacerbate inequalities.

Additionally, security measures should also be in place to ensure there is no hacking and that it is extremely difficult to create fake passports, she said.

Hoffman thought Vietnam could take its cue from the U.S., where vaccinated people are advised to continue wearing masks, staying at least six feet apart from others, avoid crowds and poorly ventilated spaces, and defer travel plans.

Regarding Vietnamese who are allowed to travel internationally with a vaccine passport, Dye said Vietnam may be concerned about the risks involved when they return. They might be required to go into quarantine.

"Again, it's about balancing risk. And that's the judgment for the government to make."

In the U.K, Dye said he and his colleagues made a list of 12 different things that need to be considered before using vaccine passports. A key factor is the science of immunity. He felt that the evidence of clear advantages of vaccination passports was becoming stronger and countries were already taking steps to introduce passports.

"I think many countries will adopt them."

Dye said countries should think about what would happen in the long term. It's very likely that Covid-19 is going to be a permanent presence in the human population. Countries have to decide how they might be managing this disease in two, three or five years. Requiring people to live under lockdowns for weeks and months at a time is simply not sustainable.

"For that reason, countries have to think about what the transition is here. What is happening now is a transition to something else as well.

"Long term thinking needs to be an important part of the way in which vaccination passports are used."

What’s in the balance

Severance said the key question for Vietnam is how ready the country is to assume risk. For instance, is the goal of resumption of travel worth the small risk of infection spread? That opens the question of how safe the vaccine passport environments are, and the answer is that people do not know for sure.

He said researchers generally think that there is little chance for a person who has been vaccinated (as prescribed) to get re-infected or infected with the disease. And in the rare case that they do get re-infected or infected, the chances of transmitting it to others under general conditions (not intimate/close contact conditions) are reduced, given viral loads and other factors.

However, he cautioned that such hypotheses do not account for other factors like the effectiveness of the vaccines against virus strains the vaccines have not been tested for. There is no perfect solution, he stressed, adding: "There is risk in every option to be considered."

He noted that a decision on vaccine passports depends on balancing a risk reducing mechanism with the need for restarting crippled economies.

"There is morbidity/mortality on each side of the equation, but only one side is currently quantifiable. Though there are statistics available for morbidity/mortality due to the disease itself, corresponding quantifiable statistics for social distancing were not readily available yet.

"Thus, such decisions are very, very difficult and not easily made," he stressed.