Effectiveness of corona vaccinations in Finland - THL publishes a new set of open data material for use by the media and citizens

Publication date 26 Nov 2021

On Thursday 25 November 2021, the Finnish Institute for Health and Welfare (THL) will publish a set of new open data material on the effectiveness of corona vaccinations in Finland. Using the new material, the user can examine the following data, broken down by age, gender and vaccination coverage:

  • incidence of infections requiring specialised medical care 
  • incidence of infections requiring intensive care
  • incidence of deaths resulting from the coronavirus
  • incidence of coronavirus infections.

The material describes the incidence of the virus in the susceptible population, which refers to persons who have not yet been infected with the coronavirus. 

With regard to the vaccination protection, the population falls into three groups: persons without vaccination coverage, persons who have a partial coverage and people who have a full coverage. For example, full vaccination coverage means that a person has received at least two doses of the coronavirus vaccine and that at least seven days have elapsed since the last vaccination. 

The material is updated once a month, upon which the data from the previous month are reviewed. The data can be viewed from the beginning of the epidemic at four-month intervals, broken down by age group, or by the entire vaccinated population, i.e., those over 12 years of age. Information on infections and deaths related to the coronavirus disease used in the material has been provided for each individual on the day of infection in order to guarantee the protection of privacy. 

The new open data will be available on the website from Thursday 25 November:
Koronarokotusten vaikuttavuus Suomessa (“Effectiveness of corona vaccinations in Finland”).

The data described in the material are only comparable when the vaccination coverage has increased

When examining the effectiveness of the corona vaccine, several factors that hinder comparison must be taken into account. The prevalence of the severe form of coronavirus disease among those affected is strongly age-dependent. In addition, different age groups have been vaccinated at different times. Within each age group, the first step to take was to start vaccinating those groups that were defined to be at risk in order to protect them. In the material, it is not possible to break down vaccination coverage by risk group. 

The incidences described in the open data, broken down by age group, are only comparable from autumn 2021 onwards, i.e., from the time when all age groups had persons with full vaccination coverage. Incidence among people with only partial vaccination coverage, i.e., among those who have only received the first vaccine dose, is poorly comparable. 

On the other hand, the intensity of the epidemic has varied at different times. When comparing groups with different vaccination coverage, the intensity of the epidemic should be taken into account in the comparison. In order to evaluate the efficacy of vaccinations, the infectious pressure should be similar in all groups compared.

The instance of the infection not controlled for age can be calculated from the data obtained from the interface of the open interface, which includes the monitoring period for population groups and the number of events. The causes of death, typically registered only after several months, are not combined with the material. No information on the actual cause of deaths related to the coronavirus is available.

The effectiveness of corona vaccinations in Finland

Further information 

Toni Lehtonen
Statistician
THL
[email protected]
 

Infektiotaudit ja rokotukset Main site Tiedonhallinta sosiaali- ja terveysalalla koronavirus_en - thlfi-en