Dutch study shows the effectiveness of COVID vaccination in reducing hospitalizations

Scientists at the National Institute for Public Health and Environment, the Netherlands, have conducted a study to explore the efficacy of coronavirus disease 2019 (COVID-19) vaccination in preventing disease-related hospitalization.

The study, which is currently available in the medRxiv* preprint server, reveals that the COVID-19 vaccination has prevented a large number of hospitalizations during the pandemic.

​​​​​​​Study: Number of COVID-19 hospitalisations averted by vaccination: Estimates for the Netherlands, January 6, 2021 through August 30, 2022. ​​​​​​​Image Credit: Hung Chung Chih / Shutterstock

Background

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has significantly burdened the global healthcare system, with more than 650 million infections and over 6.66 million deaths worldwide. However, with the deployment of COVID-19 vaccines, a considerable reduction in cases, hospitalizations, and deaths has been noticed.

Up to August 2022, the Netherlands had detected 8.5 million COVID-19 cases, resulting in 113,000 hospitalizations and 22,000 deaths. Since the initiation of COVID-19 vaccination programs in January 2021, more than 36 million vaccine doses have been administered in the country.

In the current study, scientists have estimated the number of COVID-19-related hospitalizations averted by the vaccines in the Netherlands. This would help the general population and policymakers to understand the significance of COVID-19 vaccination.

Study design

The number of COVID-19-related hospitalizations prevented by COVID-19 vaccination was estimated from January 6, 2021, to August 30, 2022 (first study period). The estimation was also done from August 2, 2021, to August 30, 2022 (second study period). During this period, all adults had the opportunity to receive primary vaccination, and children aged 12 – 17 years became eligible for the vaccination.

The number of prevented hospitalizations per age group was estimated using vaccine efficacy estimates, vaccine coverage estimates (primary and booster vaccinations), and the observed number of COVID-19-related hospitalizations. Both absolute and relative numbers of prevented hospitalizations were estimated for each study period wherein a viral variant was dominant.     

Important observations

A variation in primary vaccine coverage was observed at the end of the study period. The coverage ranged from 73% for the age group 12-49 years to 94% for the age group 70-79.

The vaccine coverage for the first booster dose varied from 42% for the age group 12-49 years to 88% for the age group 70-79. For the second booster dose, the vaccine coverage varied from 0% for the age group 12-49 years to 67% for the age group 70-79.

Overall, the vaccine coverage was higher in older age groups than in younger age groups.

During the entire study period, a total of 98,170 hospitalizations were prevented by COVID-19 vaccination. The majority of these hospitalizations (90,753) were prevented during the second study period (August 2, 2021, to August 30, 2022).

Based on the estimates, the COVID-19 vaccination prevented 57% and 67% of all hospitalizations during the first (January 2021 to August 2022) and second study periods, respectively.

The number of prevented hospitalizations was highest in the age group 70-79 years and lowest in the age group 12-49 years.

During the period when the SARS-CoV-2 alpha variant was dominant, about 8% of all hospitalizations were prevented by vaccination. During the delta and omicron waves, about 72% and 63% of all hospitalizations were prevented by vaccination, respectively.

Study significance

The study highlights the importance of COVID-19 vaccines in preventing disease-related hospitalization. The highest positive impact of vaccination has been observed in older people aged 70-79 during the delta variant outbreak.

As mentioned by the scientists, such a vaccine-mediated reduction in hospitalization rate has reduced the pressure on hospitals and healthcare workers and improved access to healthcare facilities for both COVID and non-COVID patients.