The European Union’s drugs regulator said it could make sense for countries in the bloc to administer COVID-19 vaccine boosters as early as three months after the initial two-shot regimen.

“While the current recommendation is to administer boosters preferably after six months, the data currently available support safe and effective administration of a booster as early as three months from completion,” the European Medicines Agency’s Head of Vaccines Strategy, Marco Cavaleri, told a media briefing.

He added that the public health perspective of member states would play into such a decision.

Cavaleri also said that so far no safety concerns have emerged from the United States’ vaccination campaign among five to-11 year-old children.