There is increasing momentum behind demands for vaccination certification for travellers, but international agreement is required on the standards and use of certification – and the World Health Organization remains opposed for now.

The WHO published a position paper on ‘Proof of Covid-19 vaccination for international travellers’ on February 5 which made clear: “National authorities should not introduce requirements of proof of Covid-19 vaccination for international travel as a condition for departure or entry, given there are still critical unknowns regarding the efficacy of vaccination in reducing transmission.

“People who are vaccinated should not be exempt from complying with other travel risk-reduction measures.”

It also warned: “Preferential vaccination of travellers could result in inadequate supplies of vaccines for priority populations.”

The WHO noted these recommendations are “temporary” but in line with the advice of the International Health Regulations (IHR) emergency committee on Covid-19 issued in January, which is due to be reviewed in three months.

For now, the WHO said: “A number of scientific unknowns remain concerning the effectiveness of Covid-19 vaccines.” These include “the efficacy of vaccination in limiting transmission including for variants”, the “duration of protection”, the “timing of booster vaccine doses”, and how long before travel vaccination should be required.

Some of these ‘unknowns’ may be resolved relatively quickly. But the WHO also noted: “There is limited access to Covid-19 vaccinesworldwide, particularly in low-income and lower middle-income countries.”

It warned: “Introducing a requirement of vaccination as a condition for travel has the potential to hinder equitable global access to a limited vaccine supply and would be unlikely to maximise the benefits of vaccination for individual societies and overall global health.”

The organisation also highlighted a legal issue, noting that the 196 countries signed up to the WHO’s International Health Regulations “are expected to abide by stipulations concerning the introduction of a proof of vaccination for international travellers”.

Under the IHRs, “yellow fever is currently the only disease for which countries can require proof of vaccination for international travellers”.

“Should the requirement of proof of Covid-19 vaccination for international travellers be introduced in future . . . vaccines must be universally available.”

This does not mean vaccination certification won’t become one way to facilitate travel. But the barriers may take longer to surmount than some media reports suggest. These include the technical issues. The WHO notes: “Vaccination status can easily be captured via digital means, [but] the ability to uniquely identify an individual and validate vaccination status requires international cooperation, orchestration across complex systems and widespread adoption of open interoperability standards to support secure data access or exchange.

“A digital vaccination certificate will additionally have to support the needs of national immunisation programmes.”