Significant increase in cases of tick-borne encephalitis in 2021 - national immunization programme expands within Kirkkonummi and Lohja

Edited 2nd March at 7.10: This year, vaccination recommendations for risk areas have been updated in Siuntio, not in Sipoo.

In 2021, a total of 150 cases of tick-borne encephalitis were reported to the Finnish Institute for Health and Welfare’s National Infectious Diseases Register. The number is considerably higher than in previous years. In 2020, 91 cases of TBE were reported to the register, preceded by 69 cases in 2019, 79 cases in 2018 and 85 cases in 2017. 

”During the coronavirus pandemic, people have spent more time on exercise and hobbies outdoors, visited cottages and travelled more than usual within Finland. Last summer also had excellent weather for outdoor activities. Climate change and people's awareness of tick-borne diseases can also partly explain the increase in the number of cases in recent years”, says Henna Mäkelä, Researcher at the Finnish Institute for Health and Welfare (THL).

Based on the monitoring data from the period 2017–2021, the incidence of tick-borne encephalitis has been highest in coastal municipalities, more specifically in Pargas (47 cases per 100,000 inhabitants), the province of Åland (41 / 100,000), Kustavi (37 / 100,000) and Simo (33 / 100,000). 

New areas will be included in the immunization programme in Kirkkonummi and Lohja

This year, the national immunization programme for tick-borne encephalitis will expand in Kirkkonummi and Lohja. The Masala postal code area (02430) in Kirkkonummi as well as the Ojamo (08200), Lylyinen/Hormajärvi (08450), Vohloinen/Virkkala (08700) and Kirkniemi (08800) postal code areas in Lohja are added to the programme, as the incidence of the disease has increased significantly in these areas during five years of monitoring. In Lohja, parts of these areas have already been included in the immunization programme earlier, but the areas are now included in the programme in their entirety. 

”THL monitors the occurrence of tick-borne encephalitis by municipality. However, the cases are often limited to small geographical areas, so we also calculate more detailed incidence rates for postal code areas and use them for our recommendations”, Mäkelä explains.

In addition to the new areas, the TBE vaccinations will continue in Åland, Pargas, Simo, the southern parts of Kemi, the Kotka archipelago, the Sammonlahti district of Lappeenranta, the island of Preiskari near Raahe, Kustavi, the Sipoo archipelago, the Lohjanjärvi archipelago and the Luoma area of Kirkkonummi.

Vaccinations under the national immunization programme are free of charge and are available to all permanent residents and long-term vacationers aged three or over in the area. The vaccine is especially necessary for people who spend at least four weeks in nature during the summer. 

TBE vaccinations under the national immunization programme, are only administered in municipalities that are specified in the immunization programme. Municipalities provide practical information on the vaccinations in their area. 

Vaccination recommendations in other risk areas are also updated

THL is also issuing vaccination recommendations for areas outside the national immunization programme. The vaccination recommendations for these risk areas are based on incidence and case-by-case consideration. Many municipalities around archipelagos and along the coast in particular are risk areas of tick-borne encephalitis. 

This year, vaccination recommendations for risk areas have been updated in Helsinki, Siuntio, Ingå, Kirkkonummi, Lohja and Lappeenranta. In risk areas, people must pay for their vaccination series themselves. 

THL monitors the occurrence of tick-borne encephalitis by municipality with case numbers and incidence figures. More detailed incidence figures for postal code areas are also calculated to support risk assessment. You can see the number of cases and the TBE vaccination recommendations for each municipality in the map application available on the THL website (in Finnish).

Protect yourself against tick bites

The TBE vaccine protects only against the tick-borne encephalitis caused by a virus. The vaccine does not protect against other diseases transmitted by ticks, such as borreliosis, and does not prevent ticks from attaching to the skin. All diseases spread by ticks can be prevented by protecting oneself against tick bites.

”When moving around in areas where ticks are present, it is a good idea to wear light-coloured clothes with long sleeves and trouser legs and put one's socks over the trouser legs. An insect repellent that works on ticks can provide additional protection, as can daily tick inspections”, Mäkelä says.

”However, fear of tick-borne diseases is not a good reason to restrict your activities in nature. The health benefits of outdoor recreation are much greater than the risks caused by ticks”, Mäkelä points out.

Additional information

Map presentation of the incidence of tick-borne encephalitis and vaccination recommendations by municipality 
(THL, in Finnish)

What is tick-borne encephalitis?
(THL, in Finnish)

TBE vaccine
(THL)

TBE vaccinations outside the immunization programme
(THL, in Finnish)

The difference between tick-borne encephalitis and borreliosis 
(THL blog, 16 March 2021, in Finnish)

Henna Mäkelä
Researcher
Finnish Institute for Health and Welfare
tel. +358 29 524 7488
[email protected]

Tuija Leino
Chief Physician
Finnish Institute for Health and Welfare
tel. +358 29 524 8787
[email protected]