The Institute for Health and Welfare (THL) issued recommendations on Tuesday that people over the age of 60 and those belonging to medical risk groups be offered third doses of the Covid vaccine, also known as boosters.
The institute's recommendations also apply to people residing in institutions and nursing homes, regardless of their age.
THL's chief physician and vaccinologist, Hanna Nohynek, said the effectiveness of Covid vaccines decrease over time in people who are more than 60 years of age.
"This has been observed in Finland and around the world," Nohynek told Yle.
She noted, however, that the vaccine provides very good protection for the majority of the population against severe reactions to coronavirus infections for at least six months. But the effectiveness of the vaccines appears to decline in those who are at greater risk of complications from a coronavirus infection, as well as the elderly.
"Medical literature on the immunogenicity of the vaccines support this. We want to protect our most fragile populations from dying of coronavirus. That will be best achieved by giving them a third dose," she said.
To date, every fully-vaccinated person who died of Covid in Finland was over the age of 60, according to the chief physician. A third dose improves the protection of these groups against both the risk of being infected as well as suffering from severe complications from an eventual infection.
Nearly 2 million booster doses
Nohynek said that vaccines provide 80 to 90 percent protection against suffering from severe complications to people in younger age groups, adding that there was no need yet to offer boosters to people under 60.
More than one million people in Finland are over the age of 60 and there are about 700,000 people belonging to medical risk groups. The Nordic country's total population is about 5.5 million people.
"So we are talking about booster doses for nearly two million people," Nohynek pointed out.
A booster, or third, dose of the Pfizer-Biontech and Moderna vaccines can be administered at least six months after the second dose. It is preferable for boosters to be the same vaccine as the first two, but if necessary another type may be provided, according to the THL.
Individuals in medical risk groups include people with ailments that predispose them to severe complications from Covid. These groups include, for example, recent organ transplant recipients, cancer patients currently undergoing treatment, people with severe immune system disorders, severe chronic kidney, heart or lung disease.
THL has previously issued guidance to offer booster shots to severely immunocompromised individuals. Around 77,000 third doses have already been administered across Finland to at-risk groups, health care personnel as well as nursing home residents and staff.