“It is true that there seem to be problems in Portugal when it comes to issuing certificates following the administration of a booster dose. Our experts are in contact with the Portuguese authorities”, said an official source of the community executive in a written response sent to Lusa.

The information comes after complaints from users who were unable to access the certificate that attests to the administration of the booster dose after a primary series of anti-covid-19 vaccination (two doses), as stipulated by European rules since the end of last December.

At stake is the EU digital certificate, proving the (negative) testing, vaccination or recovery of the SARS-CoV-2 virus, which came into force in the Union at the beginning of July last year.

At the end of December 2021, the European Commission announced that the EU Covid-19 Digital Certificate would now include information on booster doses of vaccines, as well as being valid for nine months for travel within the community. This last measure only comes into force at the beginning of February.

“The booster shots should appear as follows: 3/3 for a booster shot after a two-dose primary series of vaccinations; 2/1 for a booster dose after a single dose of vaccination or a dose of a two-dose vaccine given to a recovered person.

Also according to the source of the European Commission, it will be up to the Member States “to apply the coding rules and rectify the certificates if they have been coded differently”, and everything should be operational by February 1.

This certificate was created to facilitate free movement during the pandemic, but reliable data on the period for which people would be protected after vaccination with the two doses were not yet available at that time, so deadlines were not set for the period of acceptance, with the exception of recovery certificates, it being up to the Member States to define until when to accept those relating to inoculation in the context of travel.

The new rules specifically stipulate an acceptance period of nine months (from the last inoculation), given that vaccine protection appears to diminish over time.

Data from Brussels reveal that, so far, 1.17 billion certificates have been issued in the EU, in a total of 60 countries and territories from the five continents that have already joined the system.

This free pass works similarly to a boarding pass for travel, with a QR code to be easily read by electronic devices and in the citizen's national language and in English.

It was initially created to facilitate free movement within the community, but countries such as Portugal and others have expanded its use for verification in social spaces such as events and establishments.