Expert Talks: Prof Sjaak de Wit

In May 2021 Vaxxinova colleagues had the pleasure to participate in an open round table discussion with Prof Dr Sjaak de Wit.

Prof De Wit is a highly respected expert with, amongst others, a great knowledge on Infectious Bronchitis in poultry. He offers lots of interesting insights on this topic. Prof de Wit is connected to the Royal GD in the Netherlands as well as to the University of Utrecht.

Vaxxinova colleagues from Brazil, Jordan, the Netherlands and Thailand complete the expert panel in this series of videos.

The content of the videos is under copyright of Royal GD.

Poultry vaccination – how to use the available tools in dealing with respiratory viruses in poultry? There are many powerful tools available to deal with Infectious Bronchitis, and other respiratory viruses, in poultry. Vaccines, live and killed, are part of the toolbox. But there are more to consider. The question is how and when to use them. Vaxxinova’s professionals can help with this. But most important: listen to the chicken!
Learn more in this last episode with Prof. Sjaak de Wit.

Poultry IBV live vaccination – by age, by campaign or by house?
When applying Infectious Bronchitis Virus vaccination with a live vaccine, it is important to avoid the unintended spread of the vaccine between flocks or houses. This can be a complicated strategy. Prof de Wit and the Vaxxinova professionals share their view on how to best handle this.

Prof de Wit shares his view on when to vaccinate to create the optimal protection against IBV; rearing phase only or also when the birds are in lay? There is not one straight forward answer to this question, as this episode of Expert Talks will show you.

When applying IBV vaccination – how long after your flock is fully protected? And for which period of time? And what is the influence of the IBV vaccine strain? The view of Prof Sjaak de Wit and the Vaxxinova colleagues on, amongst other, these topics, is covered in this episode of Expert Talks.


Infectious Bronchitis vaccination in poultry is a never-ending topic. This episode of Expert Talks highlights various topics; the role of MDA’s in protection against IBV; possible post-vaccination reactions; IBV vaccination in MS positive birds; IBV vaccine strains and the various outcomes when using different ELISA’s.

IBV vaccination – day-old-chicks ususally receive IBV vaccine via spray application. What is the ideal dosing – volume and titres? Prof. Dr. Sjaak de Wit answers questions on this topic, as raised by Vaxxinova colleagues.




For a respiratory vaccine to be effective, the application method is really important. The Experts talk about pros and cons of drinking water application versus spray application, vaccination during outbreaks and the possibility of having an in-ovo IBV vaccine available in the future.

How effective is serology to measure Infectious Bronchitis vaccine efficacy in poultry? Is it broad enough, does it cover efficacy in day-old-chicks, does it differentiate between vaccine strain and field strain? This video shows the Expert’s discussion on this topic.

How can we evaluate the efficacy of a vaccine in the field? Prof Sjaak de Wit explains in episode 4 of “Expert Talks”, focus on ND and IB vaccines.

The experts talking on vaccination of day-old-chicks in the hatchery.

What is the best practice for mixing live respiratory vaccines? Hear the experts explaining on the topic. Key message: more is not always better.


The first video emphasizes the role of the water quality in the vaccination process.



Introduction of the speakers