"The travel rules need to take into account this volatile situation."
According to the European Centre of Disease Prevention and Control (ECDC), the vaccine begins t lose efficacy after six months. As a result, the recommendation to receive a booster shot after nine months has not been considered particularly controversial and is not an attempt to prevent tourists from visiting.
In a document seen by Bloomberg, the European Union said fully-vaccinated travellers should still be welcomed into the bloc.
How long a booster would extend a person's Covid-19 passport remains to be confirmed.
In a statement, the commission said "it can reasonably be expected that protection from booster vaccinations may last longer than that resulting from the primary vaccination series."
Since it is a proposal, 27 EU members states must approve the submission for it to be approved.
The proposal also includes a recommendation that children under six years old be exempt from travel restrictions while those aged between 6 and 12 are exempt unless they are from a high-risk country.
Currently, many European countries have slightly different regulations on how long one's vaccination status lasts and how booster shots will be managed, something the EU want to standardise.