Portugal is expanding its Covid-19 vaccine rollout to all children between the ages of 12 and 15, AP reports.

The general directorate for health’s announcement came after days of uncertainty about the move. Authorities initially limited shots in that age group to children with chronic illnesses.

Officials said the hesitancy was due to a lack of data, but Director-General for Health Graça Freitas said studies in the European Union and the United States have dispelled doubts in Portugal.

Classes are set to resume in Portugal’s schools in about four weeks. Officials estimate there are just over 400,000 children in the 12-15 age group.