The EU is proposing that EU digital COVID certs would be valid for travel for nine months after a second vaccine dose.
As booster vaccines start being administered across Europe, the European Commission is looking at revising its rules around travel.
The EU launched its digital COVID cert system during the summer, aimed at allowing travel within the bloc without the need for isolation or quarantine.
They're now proposing the certs would expire nine months after a second vaccine dose - indicating boosters would be required beyond that to renew the cert.
European Commissioner Didier Reynders said: "Our main objective is to avoid diverging measures throughout the EU. This also applies to the question of boosters, which will be essential to fight the virus.
"Among other measures, we propose today that the Council agrees on a standard validity period for vaccination certificates issued following the primary series.
"Agreeing on this proposal will be crucial for the months ahead and the protection of the safe free movement for citizens.”
The Commission is proposing the change, if agreed, would come into effect from January 10th.
They say data around booster vaccines is still emerging, but early indications are that protection from boosters could last longer than initial vaccine doses.
The Commission adds it will look at the emerging evidence to "propose an appropriate acceptance period also for vaccination certificates issued following a booster".
Meanwhile, the booster campaign is continuing to roll out in Ireland.
Health Minister Stephen Donnelly says a number of walk-in clinics across the country will be offering booster doses this weekend.
A number of vaccination centres are holding walk-ins over the coming days for boosters for Healthcare Workers and those aged 60-69. You must be due a booster (5 months since 2nd dose). Details by each vaccine centre on this page
— Stephen Donnelly (@DonnellyStephen) November 25, 2021
However, only people aged over 60 and healthcare workers will be able to avail of the walk-in clinics for now.
At least five months need to have passed since a person's second vaccine before they're eligible for a booster.