The European Public Health Agency Director Andrea Ammon said on Wednesday that giving booster doses of the Covid-19 vaccine to all adults should be considered, and priority should be given to those over 40, a major twist in the agency's guidelines.

The recommendations of the European Centre for Disease Prevention and Control (ECDC) are not binding on EU Member States, but are used in decision-making.

“Booster doses should be considered for all adults giving priority to those over 40,” Ammon said, noting that they should be given at least six months after the second dose.

In an earlier recommendation in September with the European Medicines Agency (EMA), ECDC said there was no urgent need to give booster doses to fully vaccinated people in the general population, but suggested that additional doses should be considered for people with weakened immune systems and as a precaution for the weaker elderly.

"Available evidence coming from Israel and the United Kingdom shows a significant short-term increase in protection against infection and severe disease after a booster dose in all age groups," ECDC said in a report released Wednesday.

The ECDC advises that booster doses be given to all adults, with priority given to "those aged 40 and over".

The European Commission will take this advice into account when issuing a recommendation to change the use of Covid certificates this week, officials said.

Many EU members have already started giving booster doses of the vaccine, but use different criteria for selecting groups that have priority and different time intervals between the second dose and the booster dose.