The European Commission announced Tuesday that COVID vaccine certificates in the bloc would only be valid for nine months without a booster shot.

The move comes as European countries scramble to secure more vaccine doses amid a surge in COVID cases and a spread of a likely highly transmittable new variant, omicron.

Announcing the decision, the EU Commission said that a harmonized validity period for COVID vaccine passports “is a necessity for safe free movement and EU level coordination.”

What are the new EU vaccine passport rules?

The new rule concerns traveling within the EU, but the Commission said in a statement that it recommends EU countries also apply it on a national level to “provide certainty for travellers and reduce disruptions.”

EU residents are recommended to receive a booster shot six months, at the latest, after they’re fully vaccinated. But the certificate will be valid for three additional months as a grace period to ensure access to booster doses, the Commission added.

The validity of the COVID vaccine passport after a booster shot will be extended further without a set limit, an EU official told Reuters news agency, citing a lack of scientific evidence about the duration of protection from the booster.

The Commission has also introduced a new rule for the recording of the booster shot in vaccine passports. A booster dose following a two-dose full vaccination should be recorded as “3/3” in the certificate. A single-dose vaccination followed by a booster should read “2/1.”

The rule can be blocked by a qualified majority of EU governments or a simple majority of European Parliament members. However, officials believe it has enough backing.

According to the Commission, 807 million COVID vaccine certificates have been issued in the EU so far.

Europe races to curb another COVID wave

Some EU countries have already announced similar measures.

In France, adults whose jab was more than 6-months-old would no longer have access to the national COVID pass without a booster shot. The decision comes into effect on January 15. The Netherlands has also signaled plans for a similar move.

Portugal, Ireland, Cyprus, Latvia, Italy, Greece and Austria have also brought in emergency measures requiring even vaccinated EU travelers to take pre-departure coronavirus tests or quarantine on arrival.