Project VIcTOR Study

Duration: 2021-ongoing

Impact of influenza vaccination on GP consultation rates, antibiotic usage, COVID-19 rates, influenza-related hospitalizations and mortality


Influenza vaccination is an important measure to prevent and control influenza infections. Unexpectedly, a recent Nivel-RIVM study (Caini et al, 2021) found that vaccinated individuals are more likely to be diagnosed with clinically diagnosed (not laboratory-confirmed) influenza, acute respiratory tract infections and pneumonia compared to unvaccinated individuals. This finding has led the Nivel-RIVM research team to plan a more detailed analysis of the data and extend their analysis.

Producten en dienstenMethod

The analysis will be done in the following ways:

  1. additional outcomes will be added to the analysis (antibiotic use and COVID-19)
  2. more severe outcomes will be assessed (hospitalizations and mortality)
  3. additional control diagnoses will be included
  4. the analysis will be carried out in the United Kingdom using data from the Royal College of General Practitioners.

Doel Aim

The aim of the VIcTOR study is to make a contribution in determining the impact of flu vaccination, by measuring the p chance of contacting ILI, pneumonia or BLWI, and by measuring the seriousness of occurring conditions.


The findings of our analyses will be published in a scientific journal. We will also organize a meeting with all of the key stakeholders in the Netherlands to discuss the results and their communication to a wider audience. Finally, we will establish a technical working group to see if the analysis methods developed for influenza can be applied to other vaccine-preventable diseases, in particular pneumococcal infections. We expect that the VIcTOR study will contribute to a better understanding of the impact and effectiveness of influenza vaccination.

SamenwerkingsverbandProject partners

Participating project partners are:

  • National Institute for Public Health and the Environment (RIVM)
  • The Royal College of General Practitioners (RCGP)
  • Research and Surveillance Centre based at the University of Oxford

Panels met patiënten, cliënten en burgersNivel project team

Participating Nivel researchers are:


ZonMw Infectious Disease Control Program

Meer wetenWant to know more?

For more information on this project, please feel free to get in touch with the Nivel expert(s) involved. You will find them on the right, together with the (future) Nivel deliverables (publications) and other relevant content.


Paget, J. Project VIcTOR Study . From: [Last update 02-December-2021; consulted on 17-January-2022]. URL: