IPPE: Why infectious bronchitis outbreaks still happen

15 September 2025

5 minute read

By: Sarah Mikesell

North America

Dr. Brian Jordan, an associate director of Outcomes Research at Zoetis, spoke to The Poultry Site’s Sarah Mikesell at IPPE 2025 in Atlanta, Georgia, USA, about infectious bronchitis vaccination.

Despite having a vaccination program in place, infectious bronchitis virus outbreaks are a challenge that poultry producers continue to face. What are some of the reasons outbreaks can still occur?

There are many factors that can influence your bronchitis control strategy. Sometimes we have variant viruses that emerge, and regardless of what type of vaccine or vaccine program you use, you may not have protection against a new strain. Those events can be rare, and we're working to understand when those events may occur to try to head them off.

By far, the more common reason we still have disease associated with infectious bronchitis is misapplication, mishandling or poor application of our vaccines. All commercially raised broilers in the US are vaccinated against infectious bronchitis oftentimes with multiple strains. When we do this process for the vast number of broilers that are produced every day – with so many birds going through the hatchery – there's a lot of opportunity for mistakes to occur, and we do see that happen.

What can producers do to support infectious bronchitis vaccination efficacy?

First, ensure that the vaccines are handled correctly in the hatchery. Some vaccines are frozen products that need to have care taken when thawing and mixing. Some are lyophilized that are a little more temperature stable, but they can also be influenced by improper handling practices.

Second, ensure that your machinery in the hatchery is functioning properly to apply the vaccine to the chicks. There are several types of application cabinets — some are spray, some are gel. All of them have certain pain points within the system where a defect or operation issue can really influence the effectiveness of getting the vaccine to the birds.

Last, the follow-up step is to go check the birds to ensure the vaccine got to the chicks and that is a process of checking vaccine takes. That's a service that we at Zoetis provide, and it's an effective way for producers to help understand how successful the process of vaccination was in addition to how well your vaccines are reacting and replicating within your birds.

What are some monitoring steps that can help ensure an effective IB vaccination program?

There are really two separate places within the production cycle where monitoring or surveillance are highly effective for infectious bronchitis.

The first step is measuring vaccine takes, as I just mentioned. We recommend, five to seven days post-vaccination, go in and sample chicks. We use real-time PCR now that's a very rapid, inexpensive and sensitive molecular diagnostic test to measure how many chicks got the vaccine and how much vaccine they got.

With those metrics, we can also understand the influence that certain vaccine combinations have on each other. It's not just one individual vaccine. It's looking at your whole vaccine program and building that program out to be the most successful it can be.

The second step is, later in the life of the flock, doing routine disease surveillance. Most poultry companies do posting sessions once a quarter where they sample birds across all ages in their complex. At this time, they're doing a lot of intestinal health checks, like for coccidiosis, a major disease. They're sacrificing birds to do these health checks. There are tracheas that we can sample for our respiratory pathogens, as well. This gives us a clear picture of how our vaccines are clearing from the flock and when any potential disease challenge viruses are coming into the flock.

These surveys are typically done every time you do a posting session. Whether it’s done once a quarter or on a regular cadence, it builds a large data set to understand how each complex or each company or even each region within a complex is behaving year after year, season after season.

What's your take-home message about IB vaccination?

This would be true for any of the live vaccines we give in the hatchery – vaccination for bronchitis is a very straightforward process that we repeat millions of times per week. With that number of repetitions, there are always ways that mistakes can be introduced.

Ensuring that your birds get the vaccine is the first and probably the most critical step to building a good vaccine program to protect birds from infectious bronchitis respiratory disease.

We sometimes forget but the devil is in the details, right?

That's exactly right -- the devil is in the details. It's something that we at Zoetis are familiar with through our history with Embrex. The amount of training, resources, and knowledge that goes into the process of the in-ovo vaccination side.

For a long time, spray application of vaccines in the hatchery has almost been an afterthought. Because when the chicks move through the spray cabinet, they get sprayed. They look like they have vaccine. Until the development of these molecular diagnostics tools, we really didn't know how much vaccine they received. In the last seven years, we've been able to do a lot of testing and develop data to understand a lot of hatcheries were not doing an excellent job of vaccinating birds.

We also found that not all vaccines behave the same way either — not just within a particular company, a particular strain across different strains, or between different serogroups. There's a lot of nuances that we're learning now. With diagnostic tools, we can help build a better vaccination health program, not just individual disease control.

That's why your title incudes “Outcomes” – because you're looking at the impact of all these outcomes?

Yes, my role at Zoetis is outcomes research, which is research to support our customers. It's developing and designing trials, and developing data sets that are real world, which mean something to our customers and can help them be better in their processes to control respiratory disease or whatever the project may be about.

Any concluding thoughts?

In terms of controlling bronchitis and other respiratory pathogens, we offer a variety of services to support those programs from hatchery audits, performance evaluations on your spray cabinets and performing the diagnostic assays that we provide as a service for our customers. And it’s not just a service for bronchitis. We have a lot of assays that are new to Zoetis that we have introduced and rolled out in the last six to 12 months.

I would encourage anyone who wants to better understand how their respiratory control program is working to reach out, and we'd be glad to run some samples and generate some data. We can learn together.

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