Vaccine effectiveness has been slightly lower in the last 8 weeks compared to the entire period from 11 July to 14 November 2021. There are various explanations for this. One is that people who have recently been admitted to hospital completed their vaccination series longer ago, on average, than people who were admitted in summer. The increased virus circulation in recent months may also partly explain it.
Vaccinated people much less likely to be admitted to hospital or ICU than unvaccinated people
In the past 8 weeks, the chance that a fully vaccinated person with the coronavirus SARS-CoV-2 would be admitted to hospital was 11 times lower than for a non-vaccinated person. The chance of ICU admission was 25 times lower.*
Vaccine effectiveness among people aged 70+
Vaccine effectiveness against severe COVID-19 has been slightly lower among older people than among other age groups, starting from the first estimates in August 2021. In the past eight weeks, vaccine effectiveness among people aged 70 years and older was 84% against hospital admission and 93% against ICU admission. Vaccine effectiveness remains high in this age group as well. The number of hospital and ICU admissions per 100,000 people in this age group is still much higher among unvaccinated people than among vaccinated people (Figure 1).
Figure 1. Incidence per 100,000 people of the number of COVID-19 (A) hospital admissions and (B) ICU admissions among unvaccinated, partly vaccinated and fully vaccinated people, by age group. Due to reporting delays, the data for the past few days is not yet complete (indicated in light blue).
The analysis is based on NICE data on hospital admissions of patients with COVID-19 admitted until 23 November 2021. The data was enriched on 24 November 2021 with vaccination data from the central COVID-19 vaccination register (CIMS). The method used to calculate vaccine effectiveness is explained in the report: Study: Effectiveness of COVID-19 vaccination against hospital and ICU admission in the Netherlands
More information is available in previous updates on effectiveness of COVID-19 vaccines.
Please note: raw data cannot be published due to its privacy-sensitive nature.
* These probabilities can be derived directly from vaccine effectiveness: reduced probability=100/(100-vaccine effectiveness).