First estimates of the effectiveness of COVID-19 vaccines have been received – vaccinations have reduced cases leading to hospital treatment

Publication date 31 Mar 2021

The first preliminary research results on the effectiveness of coronavirus vaccines have been received in Finland.  The results are based on a register study carried out by the Finnish Institute for Health and Welfare (THL), in which the Care Register for Health Care, the National Infectious Diseases Register and the National Vaccination Register have been used.

Vaccination reduced the number of severe coronavirus diseases requiring hospital treatment by an average of 74% (95 % confidence interval 42–88 %)  in the elderly and 84% (95 % confidence interval 34–96%) in the risk groups. 

Vaccination data have been included for all people who have received at least one dose of the coronavirus vaccine. The effectiveness of vaccines has been assessed separately for those over 70 years of age and for those aged 16–69 in risk groups due to an illness. 

Preliminary assessments of effectiveness in line with international results

The study compares the risk of hospital treatment due to coronavirus disease with those who have been vaccinated and those who have not been vaccinated. The assessment of effectiveness of the vaccination has been standardised according to age, gender, the epidemic situation in the area and whether the person vaccinated because of his or her underlying disease has been in the first or second risk group to be vaccinated.

“Assessments of the effectiveness of vaccination are well in line with international results: the effectiveness after four weeks from receiving the first dose of vaccine has been 78% in Israel, 81% in Scotland and 71–80% in England. The results depend, among other things, on the vaccine product used and the age of the subjects”, says Tuija Leino, Chief Physician from the Finnish Institute for Health and Welfare.  

All vaccine products used have been combined in the analysis. In Finland, the majority of mRNA vaccines have been administered to the elderly and the majority of adenovirus vector vaccines to those at risk.

Research results will be specified as vaccination progresses

Those who have needed hospital care due to coronavirus disease, have been hospitalised within an average of 10 days of contracting the infection. The effectiveness of vaccination to prevent hospitalisation has been assessed when at least 30 days had passed since the vaccination.  

“The effectiveness of vaccines may have been underestimated since those who, due to health reasons are the most fragile and who likely experience a lower efficacy of the vaccine, have received the vaccine first. However, the material is constantly supplemented and we will get more reliable results in the near future”, says Eero Poukka. Medical Specialist.

Material accumulated between 27 December 2020 and 28 March 2021 has been included in the study. The results mainly concern the efficacy of a single dose of vaccine, as only one in ten people who had received an mRNA vaccine had received another dose of vaccine during this period, whereas no one who had received an adenovirus vector vaccine had received a second dose.

Further information:

Tuija Leino 
Chief Physician
[email protected] 

Eero Poukka 
Medical Specialist
[email protected]

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