Finland is to recommend every adult gets a Covid booster shot between five and six months after their second dose of Covid vaccine, and that children at risk of severe Covid should also be vaccinated.
Third doses had already been recommended for those aged over 60, those who had a shorter gap between their first two doses and those caring for Covid patients.
"The goal of the recommendation is to reduce the number of Covid infections and prevent the spread of the virus," said THL Chief Physician Hanna Nohynek in a press release.
"Third doses reduce the spread of the virus in the population and improve protection against serious disease."
The THL is also recommending vaccination for children aged 5-11 in risk groups. Vaccinations could begin as early as Christmas, according to the agency. It said it needed more information on the safety of Covid vaccines for children before it recommended vaccinating them more widely.