Skip to main content

Does a vaccination work better in the morning or evening? Koen & Tamara will find out

February 12, 2024

In the fall of 2022, PhD candidates Koen Vink and Tamara Brouwers started with their BioClock project at the RIVM. Supervised by prof. Debbie van Baarle and prof. Jacco Wallinga, they investigate the interaction between the circadian clock and the immune system. More specifically, they look at the timing and dosing of vaccinations on the immune response and burden of disease. With epidemiological and modelling work (Koen) and preclinical and clinical studies (Tamara), in the next few years they want to investigate how this exactly works and how it changes in elderly and shift workers. We will introduce them below.

Who are you?

My name is Koen Vink. Originally I’m from Venlo, but I live in Nijmegen for 6 years now. In my leisure time I love to play basketball, travel, play the piano, and spending time with friends.

What is your background?

I studied biomedical sciences at the Radboud university, Nijmegen. Because of my interest in infectious diseases I followed the master specialisations in epidemiology and immunology. After graduating I was fortunate enough to start a PhD track within the Bioclock consortium.

What is your project about?

The project is about the chronobiological optimisation of vaccinations. So I’m interested in finding out at what time of the day vaccines should be administered to offer the best protection against pathogens, like the influenza virus and SARS-CoV-2. Specifically, the objective is to determine the effect of vaccination timing on the immunological response and to assess the resulting change in the burden of the disease.

When did you first hear about the biological clock?

During my study I learned that a lot of biological functions in the body follow a circadian rhythm, and are regulated by our biological clock. When applying for this job I learned more about the immune system and its circadian rhythm, which implies that the timing of vaccinations could impact the effectiveness of vaccines.

What is something people should know about you?

Since the beginning of the COVID-19 pandemic I started learning Italian, because I just think it’s a fun language!

To contact Koen, send an email: koen.vink@rivm.nl

Who are you?

I am Tamara Brouwers. I am 24-years old and live in Utrecht. I dedicate my free time to swimming, cycling and running, because I like to run marathons and participate in long distance triathlons. Next to doing sports, I love to eat, read books, watch some feel-good series on Netflix and hang out with my friends.

What is your background?
From 2016-2020 I participated in the Bachelor Program Biomedical Sciences at Utrecht University. During my Bachelor, I also finished a minor in Mathematics. Following my Bachelor, I started the Master Infection and Immunity at Utrecht University, which I graduated from last October. On November 1st, I started my PhD at the RIVM.

What is your project about?
The ultimate goal of my project is to determine the effect of the dosing time of vaccination on the antibody and cellular immune response to vaccination. I will look into the circadian rhythm of immune cells and determine whether these rhythms change with age. Moreover, I will perform a randomized clinical trial to determine the effect of administration time of influenza vaccination on the antibody and cellular immune response in night shift versus day shift workers.

When did you first hear about the biological clock?
I only first heard about the field of chronobiology when I saw the vacancy for this PhD position. I am very much looking forward to dive into the world of chronobiology and meet a lot of people who also work in this field.

What is something people should know about you?
I am obsessed with cats!

To contact Tamara, send an email: tamara.brouwers@rivm.nl


NWO logo



The BioClock Consortium is funded by the NWA-ORC programme of the Dutch Research Council (NWO; project number 1292.19.077).