The Government web-site TravelHealthPro recommends the following vaccinations for visitors to the Baltic countries:
Tetanus, Polio, Diphtheria
boosters up-to-date
MMR
up-to-date
Tick Borne Encephalitis (TBE)
for travellers to the area around Stockholm, Finland and Estonia, especially if likely to be exposed to woodland areas.
The locals take it very seriously.
This vaccine is not available free on NHS, but can be arranged through your GP. Three doses are needed; the first around 3 months before travel, the second before travel and the third a year later to give lifetime immunity.