Among people who had received a repeat vaccination in the autumn round, the risk of hospital admission due to COVID-19 was 26% lower in the age group of 40-59 years, 57% lower in the age group of 60-79 years, and 51% in the age group of 80 years and older. This was in comparison to people the same age who had received at least one vaccination, but had not received the repeat vaccination in the autumn round.

People aged 60 years and older have a higher risk of hospital admission, which is why they received a personal invitation for the repeat vaccination in the autumn round.

In the past 8 weeks (10 January – 6 March 2023), the risk of hospital admission for people aged 60 years and older who received a repeat vaccination against COVID-19 in the autumn round was 46% lower than for people who had previously received at least one COVID-19 vaccination, but had not received a repeat vaccination in the autumn round. Similarly, the risk of ICU admission was 36% lower.

Comparing the group who had the repeat vaccination in the autumn round to the group who had at least one COVID-19 vaccination, but did not receive the repeat vaccination in the autumn round, we see that the relative risk difference of hospital and ICU admission is gradually decreasing over time. There may be various reasons for that narrowing gap. For example, it is likely that the effectiveness of the vaccine diminishes gradually over time. Immunity built up by infections probably also contributes to the decreasing relative risk difference in admissions when comparing people who did or did not get the autumn vaccination.

People who do not have the same vaccination status may also have differences in vulnerability (underlying health conditions) or the number of SARS-CoV-2 infections they have had. Therefore, a comparison of hospital and ICU admission rates between people with a different vaccination status cannot be exclusively used to indicate vaccine effectiveness.

Everyone who has been invited to get a COVID-19 vaccination in the basic series, but has not yet done so, can still be vaccinated. In addition, since 19 September 2022, it is possible to get a repeat vaccination against COVID-19. This repeat vaccination in the autumn round is available to everyone aged 12 years and older who has at least completed the basic series of COVID-19 vaccinations. The vaccination is available from 3 months after the most recent COVID-19 vaccination or SARS-CoV-2 infection.