'Need to be very careful'

Mike Ryan, executive director of the Health Emergencies Programme of the World Health Organization, said on Monday that the use of certification of vaccination as a requirement for travel is not advised at the present time because vaccination is not available around the world, especially on an equitable basis. He noted that there are also people who for whatever reason cannot be vaccinated or do not wish to be vaccinated.

"So this is a very important societal discussion, that I think we need to be very careful," he said.

But Ryan praised the digital certification of vaccination itself as a positive development in public health architecture, adding that the WHO has an in-house team working on the subject.

Regarding such certification, Kate O'Brien, the WHO's director for immunization, vaccines and biologicals, said, "What we are doing is establishing the standards for those kinds of records", and establishing the technical basis "which any given app or platform would have to meet" to ensure that all those elements are in place.

Civil liberties groups have said people who don't want to get the vaccine due to religious or cultural reasons could be blocked from some aspects of daily life, while a digital-based app could penalize those who don't have a smartphone.

"I foresee vaccine passports being used as a way to further disenfranchise people," Alexis Hancock, director of engineering for the Electronic Frontier Foundation, a San Francisco-based nonprofit digital rights group, told China Daily. "For example, (its) being used as a common restriction tactic on the marginalized but not as stringent for the more privileged."