In the period from 1 February 2022 to 3 May 2022, vaccine effectiveness of the repeat vaccination against COVID-19 in preventing hospital admission was 88%. In the same period, vaccine effectiveness in preventing hospital admission was 78% among people aged 70 years and older who had received the booster jab but not the repeat vaccination, and 37% among people who had only received the basic series of COVID-19 vaccinations. This means that the risk of hospital admission after a booster jab is more than 3 times lower than for people who have only received the basic series.

The booster vaccination continues to provide effective protection against hospital or ICU admission due to COVID-19, even three months later. However, we do see that effectiveness wanes over time. In the group of people aged 70 years and older, the repeat vaccination seems to restore vaccine effectiveness against hospital admission to the level just after the booster vaccination. Estimates for effectiveness of the repeat vaccination among people aged 60-69 years are not yet definite, due to low numbers.T

he difference in the risk of hospital and ICU admission for vaccinated and unvaccinated people has grown smaller. This could indicate that vaccine effectiveness is waning. However, previous SARS-CoV-2 infections also help people to build up immunity against severe COVID-19 in the event of a new infection. The number of hospital and ICU admissions is currently low in all age groups.

In the first few weeks after 1 February 2022, less than 10% of hospital admissions were caused by the BA.2 subvariant of Omicron. As of 3 May 2022, that percentage has risen to more than 98%.