“In the absence of evidence on the efficacy of a vaccine dose in previously infected individuals against the Delta variant, […] ECDC advises administering a full course of vaccination to all individuals at increased risk of serious Covid-19, regardless of the previous infection”, states the organism in a written response sent on 2 July to the Lusa News Agency.

The position comes at a time when countries such as Portugal, Austria, Croatia, Estonia, France, Germany, Ireland, Netherlands, Slovenia and Spain administer only one dose of vaccine to previously infected people, and when the Delta variant of SARS-CoV- 2, initially detected in India and more transmissible than any other, is spreading in the European Union (EU).

In the case of Portugal, only one dose of vaccine is recommended to these people – for vaccines with a two-dose schedule – and it is administered six months after the infection.

Asked about this option by countries, including Portugal, ECDC tells Lusa that “national vaccination strategies should take into account the local epidemiological context, among other things”.

The European Medicines Agency (EMA) informs that "decisions on how vaccines should be administered continue to be the responsibility of the specialized bodies that guide the vaccination campaign in each Member State".

"These organisms are in a better position to take into account local conditions, including the spread of the virus - especially any worrying variants -, the availability of vaccines and the capacities of the national health system", the EMA tells Lusa.

The European regulator said that the vaccines it authorized "protect against all the strains that are dominant in the EU", including Delta, although it admits the need for "surveillance".

In most European countries, two doses are given even to those who were previously infected with the virus, such as Belgium, Czech Republic, Denmark, Finland, Hungary, Latvia, Lithuania, Luxembourg, Malta, Poland, Romania, Slovakia and Sweden, according to data of the ECDC.

Four anti-Covid-19 vaccines are approved in the EU: Comirnaty (Pfizer/BioNTech), Spikevax (Moderna), Vaxzevria (AstraZeneca) and Janssen (Johnson & Johnson group).

In a report released last week, ECDC estimated that the Delta variant of SARS-CoV-2 was responsible for 90% of new infections in Europe by the end of August and an increase in hospitalizations and deaths, calling for rapid advances in vaccination in the EU.

In that document, the European center explained that "those who received only the first dose - of a two-vaccination process - are less protected" against the Delta variant.