Environmental Assessment for the Canadian Licensing of Ceva Animal Health Inc.'s Infectious Bronchitis Vaccine, Georgia Type, Live Virus

August 7, 2025

Prepared and revised by the Canadian Centre for Veterinary Biologics (CCVB) of the Canadian Food Inspection Agency (CFIA), this environmental assessment includes information that was current at the time of its preparation. It is possible, however, that the situation may have changed since that time. Please consult the CCVB if you have any questions.

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Ceva Animal Health, LLC's Bronchitis Vaccine, Georgia Type, Live Virus (Trade Name: Cevac IBron) contains a live infectious bronchitis virus (IBV), derived from a Georgia type strain, that has been rendered avirulent through serial passage through the host species. The Cevac IBron vaccine is labelled for use in chickens at 1 day of age or older, for use against IBV Georgia 08 strain, Georgia 13 strain and Delmarva 1639/11 strain. As part of the requirements for licensing this product in Canada, the Canadian Centre for Veterinary Biologics (CCVB) of the Canadian Food Inspection Agency (CFIA) has conducted an environmental assessment for the vaccine organism. This public Environmental Assessment summary document contains information on the molecular and biological characteristics of the live vaccine organism, target animal and non-target animal safety, human safety, environmental considerations and risk mitigating measures.

1. Introduction

1.1 Proposed action

The CCVB is responsible for licensing veterinary biologics for use in Canada. The legal authority for the regulation of veterinary biologics in Canada is provided under the Health of Animals Act and the Health of Animals Regulations. Any veterinary biologic manufactured, sold or represented for use in Canada must comply with the requirements specified by the CFIA regarding the safety, purity, potency and efficacy of the product Ceva Animal Health, LLC (Lenexa, Kansas, U.S.) has submitted an application to license the following vaccine in Canada:

  • Bronchitis Vaccine, Georgia Type, Live Virus (Cevac IBron, lyophilized); CCVB File 800VV/B1.27/B10
  • Bronchitis Vaccine, Georgia Type, Live Virus (Cevac IBron, frozen); CCVB File 800VV/B1.28/B10

This environmental assessment was prepared by the CCVB as part of the overall assessment for licensing this vaccine in Canada. It is based on information provided by the manufacturer as well as information independently obtained from the published literature.

1.2 Background

Bronchitis Vaccine, Georgia Type, Live Virus (hereafter referred to as Cevac IBron) is manufactured in the United States (U.S.) by the company, Ceva Animal Health, LLC, which holds a United States Veterinary Biologics Establishment Licence (No. 368) issued by the Centre for Veterinary Biologics of the Unites States Department of Agriculture (USDA-CVB). The vaccine has been licensed for sale since 2015 in the U.S. and is widely used. The vaccine contains a live infectious bronchitis virus that has been attenuated by serial passage of a Georgia type virus through the host species (chicken).

IBV is a significant pathogen of commercial meat-producing and egg-laying birds and is ubiquitous in most parts of the world where poultry are reared Footnote 1 Footnote 2. This highly contagious virus typically causes acute respiratory signs and production losses, although certain strains can cause interstitial nephritis and result in increased mortality rates Footnote 1. IBV infections additionally predispose chickens to secondary pathogens, which can result in chronic complicated airsacculitis Footnote 1. From 2016 to present time, the Delmarva (DMV)/1639/11 strain has become one of the most important viral chicken pathogens in Ontario causing severe disease affecting all chicken commodity groups Footnote 3.

Transmission of IBV occurs directly from the respiratory tract of infected birds, via the aerosol route, although transmission through infected faeces has also been documented; vertical transmission and vector-borne transmission have not been observed Footnote 4 Footnote 5. Disease management and prevention strategies usually include the use of live or inactivated vaccines, along with improvements to animal husbandry, facility management and biosecurity practices. Footnote 4

2. Purpose and need for proposed action

2.1 Significance

The labelling for Cevac IBron indicates that the vaccine is intended for administration to chickens, at 1 day of age or older, via the intranasal (coarse spray) route or the oral (gel droplet) route, against IBV GA08, GA13 or DMV/1639/11 types. It is a live IBV vaccine.

2.2 Rationale

The CCVB evaluates veterinary biologic product submissions for licensure under the Health of Animals Act and the Health of Animals Regulations. The general criteria for licensing are as follows:

  • the product must be pure, safe, potent and efficacious
  • vaccine components must be relevant to Canadian disease conditions
  • foreign products must be licensed in the country of origin; and
  • the product must be produced and tested in accordance with generally accepted good manufacturing practices

This U.S. origin vaccine meets these general criteria and thus was evaluated for licensing by the CCVB.

3. Alternatives

The 2 alternative options being considered are:

  1. to issue a Permit to Import Veterinary Biologics allowing the importation of Cevac IBron, if all licensing requirements are met; or
  2. not to issue a Permit to Import Veterinary Biologics if licensing requirements are not met

4. Molecular and biological characteristics of parental and vaccine organisms

4.1 Identification, sources and strains of parental organisms

The parental strain of IBV was isolated in 2013 from the tracheas of unvaccinated, specific pathogen free (SPF) sentinel chickens placed in a broiler house with high incidence of respiratory disease in Alabama, U.S. This strain was shown by genotyping to be a Georgia 08 serotype.

4.2 Source, description and function of foreign genetic material

No foreign genetic material has been added.

4.3 Method of accomplishing genetic modification

To attenuate the isolate, Ceva passed the virus in SPF chicken embryos to produce the Master Seed Virus (MSV) used in this vaccine.

4.4 Genetic and phenotypic stability of the vaccine organism

The manufacturer examined the stability of the vaccine organism after serial back passage to "X+5", the highest passage used in vaccine production. The deoxyribonucleic acid (DNA) sequence alignment of the hypervariable region of the spike gene was the same for the initial MSV and the virus obtained after 5 serial passages through SPF chickens. These data support the genetic stability of the attenuated virus in the host species. See section 6.4 of this document for further details.

4.5 Horizontal gene transfer and potential for recombination

As a single-stranded ribonucleic acid (RNA) virus of the coronavirus family, IBV has a substantial capacity for spontaneous mutation and genetic recombination and numerous studies have confirmed its ability to rapidly evolve Footnote 6 Footnote 7. Many variants of IBV have been identified and continue to emerge Footnote 8 Footnote 9

Recombination events occur during nucleic acid replication because the virus replicates its RNA using a discontinuous transcription mechanism, which inherently favours recombination events Footnote 7 Footnote 10 Footnote 11 Footnote 12. The chance of an in vivo recombination event for the vaccine organism has not been quantified, but it is expected to be the same as that for a wild type IBV field strain and for other live strains of IBV contained in commercially-available vaccines licensed in Canada.

4.6 Host range/specificity, tissue tropism and shed/spread capabilities

The chicken is considered the natural host species for IBV, although susceptibility can vary by breed Footnote 4. No significant clinical disease was observed and no viral re-isolation was possible after experimental challenge of other avian species (turkeys, ring-neck pheasants and quail) with IBV Footnote 4. Although it has been suggested that other species of birds may play a role in global dissemination of IBV strains, evidence to support this speculation is lacking Footnote 2.

Wild type field strains of IBV typically infect chickens via the nasal/oral mucosa to replicate within epithelial cells of the respiratory tract. In some cases, the infected animal will become viremic and the virus will migrate to other tissues (for example reproductive tract, kidney and gastrointestinal tract), depending on the strain of IBV Footnote 13. No tissue tropism studies were provided by the manufacturer for the vaccine organism, but its tissue tropism is expected to be similar to that of the parent organism (which primarily infects the respiratory tract) Footnote 14.

The manufacturer has not conducted studies to determine the shed/spread capabilities of the vaccine organism. It is well documented in literature that IBV spreads from exposed chickens to in-contact chickens Footnote 4. Both the parent organism and the vaccine (attenuated) organism are expected to shed from exposed /vaccinated chickens and spread to in-contact chickens.

4.7 Comparison of the vaccine organisms to parental properties

The parental isolate was identified as IBV by the typical embryo lesion pattern in 9 to 11-day-old SPF embryos. These lesions included stunting and curling of the embryo and clubbed down. To attenuate the isolate, Ceva passed the virus 51 passages (P51) in SPF chicken embryos to produce the master seed. Passages P37 and P50 (premaster seed) were compared to P1 for safety 28 days post vaccination in day-old SPF chicks. Clinical signs and histopathological analysis of tracheal and kidney tissues demonstrated that P50 was safe.

4.8 Route of administration/transmission

The Cevac IBron vaccine is to be administered by the intranasal route (coarse spray) or intraoral route (gel droplet), to chickens at 1 day of age or older. As per shed/spread data on file and general properties of IBV, transmission from vaccinated chickens to in-contact unvaccinated chickens is possible. See also section 4.6 of this document.

5. Human safety

5.1 Previous safe use

This product has been licensed for sale in the U.S. since October 2015.

5.2 Probability of human exposure

Individuals administering Cevac IBron to chickens could on occasion become exposed to the vaccine in the event of accidental spillage or misdirection/malfunction of spray equipment.

Human exposure to the IBV is also possible for individuals handling vaccinated animals based on the manufacturer's ability to recover shed vaccine virus in animal secretions post-vaccination.

5.3 Possible outcomes of human exposure

Human exposure to the vaccine organism is not expected to be a health concern. Field strains of IBV are not pathogenic to humans Footnote 15 and there is no reason to believe the attenuated vaccine virus would be pathogenic.

5.4 Pathogenicity of parent microorganisms in humans

IBV is not known to be pathogenic to humans Footnote 15. Field strains of IBV are prevalent in many countries, including Canada and are not recognized as a zoonotic concern for the farmers and veterinarians routinely exposed to these viruses.

5.5 Effect of attenuation on pathogenicity in humans

Attenuation of this strain has eliminated the ability of the vaccine organism to cause disease in chickens and, if anything, this has presumably further reduced the chance of the virus being pathogenic to humans.

5.6 Risk associated with widespread use of the vaccine

No risks to human safety associated with the widespread use of the vaccine have been identified.

6. Animal safety

6.1 Previous safe use

Prior to licensing in the U.S., Cevac IBron was field tested in day-old chicks on several farms in the U.S. No increases in morbidity, mortality or condemnation rates were seen in association with the use of the vaccine.

An overdose study was also performed by the manufacturer. No increase in morbidity or mortality was seen in chicks vaccinated at 1 day of age with 10 times the recommended dose, though mild/typical post-vaccination signs were seen.

Over 21 billion doses of IBron have been sold in the U.S. from 2015 to 2025 with no adverse events reported.

6.2 Fate of the vaccine in target and non-target species

The manufacturer did not provide data related to fate of the vaccine organism in target or non-target species, however it is expected to be similar to that of the parent wild type organism. The target species of the vaccine is the chicken, and replication in other species is not expected. The expected tissue tropism of the vaccine organism is expected to be respiratory tract (and possibly the kidney, reproductive system and/or alimentary tract). See also section 4.6 of this document.

6.3 Potential of shed and/or spread from vaccinate to contact target and non-target animals

The manufacturer has not conducted studies to determine the shed and/or spread of the GA08 strain from vaccinated chickens to either unvaccinated chickens or animals of non-target species, but data on Mass, Conn and Ark strains were provided It is well documented in literature that IBV spreads from exposed chickens to in-contact unvaccinated chickens Footnote 4. The vaccine organism (attenuated) is expected to shed from vaccinated chickens and spread to in-contact unvaccinated chickens.

Based on the literature and the properties of the parent organism and other vaccine and wild-type IBV strains, the vaccine organism is not expected to spread from vaccinated chickens to in-contact animals of non-target species (avian, mammalian, etc.)

6.4 Reversion to virulence resulting from back passage in animals

The manufacturer performed a back passage study in chickens which involved the vaccine virus being administered by the route of administration indicated for vaccination. For this study, day-old SPF chicks were vaccinated with the MSV (via the intraocular and intranasal routes) for the first pass. The vaccine virus was then recovered from tracheal swabs taken from these chicks and used to inoculate the second group of chicks. Tracheal swabs were obtained from the second group of chicks and recovered vaccine virus was used to inoculate the third group and so on, until the final inoculation of a sixth group of chicks. No morbidity or mortality was seen in any of the experimental animals. The IBV obtained from the tracheal swab of the sixth group of chicks was genotyped and the spike gene sequence was found to be 100% identical to that of the MSV used to inoculate the first group of chicks. These results suggest that the vaccine virus does not tend to revert to virulence after serial back passage in the host species. See also section 4.4 of this document.

6.5 Effect of overdose in target and potential non-target species

The vaccine was tested in day-old chicks, which is the youngest age for which the vaccine is recommended, at 10 times the recommended dose. No safety concerns were identified.

6.6 The extent of the host range and the degree of mobility of the vaccine organism

Like wild-type IBV and the parent organism, the host range of the vaccine organism is expected to be limited to chickens, though the manufacturer has not submitted any studies to confirm this.

7. Affected environment

7.1 Extent of release into the environment

Release into the environment is possible with this vaccine. Release could occur in cases of accidental spillage or via shedding from vaccinated animals (respiratory secretions; possibly feces/litter).

7.2 Persistence of the vaccine organism in the environment and cumulative impacts

The attenuated MSV virus of the vaccine is not expected to be any more persistent in the environment than field strains of IBV which are prevalent in Canada. IBV, as a single-stranded RNA virus, is susceptible to many common lipophilic disinfectants and solvents Footnote 7 Footnote 9. Ultraviolet radiation can inactivate the virus after 8 to 12 hours of exposure (9).

7.3 Extent of exposure of non-target species

Animals of non-target species may become exposed to the vaccine virus because, like wild type IBV (including the parental organism) and other live IBV vaccines, the vaccine virus is shed in the respiratory secretions of chickens after vaccination. Manufacturer's studies have confirmed this.

7.4 Behaviour of parent and vaccine microorganisms in non-target species

Despite the fact that non-target species could possibly be exposed to the vaccine organism, they are not expected to become infected or to suffer morbidity/mortality (as would be the case for the wild type IBV/parent organism and other live IBV vaccine organisms) due to the avirulent nature of the vaccine organism and the fact that IBV appears to have a very narrow host range.

To date, IBV has not been detected in any species other than chickens and experimental infection of other avian species resulted in no clinical disease and no virus re-isolation from tracheal swabs Footnote 2 Footnote 4. See also section 4.6 of this document.

8. Environmental consequences

8.1 Risks and benefits

This vaccine has been shown to help reduce clinical signs of IBV, including the Georgia 08, Georgia 13 and Delmarva 1639/11 strains. Co-administration with a Mass IBV vaccine strain has been demonstrated to prevent transmission of DMV/1639/11 from challenged vaccinates to non-vaccinated contacts Footnote 16. The challenge viruses used in pivotal efficacy studies were of U.S. origin, but the manufacturer has also performed a study demonstrating efficacy against a Canadian Delmarva challenge isolate, in a separate study.

This live vaccine is derived from a MSV of the Georgia 08 serotype. Live vaccines derived from this serotype have not been allowed in Canada to date. Vaccinated chickens may spread the avirulent vaccine strain of IBV to in-contact unvaccinated chickens.

Though the MSV has not shown a reversion to virulence in the manufacturer's study, there still exists a possibility that the vaccine could experience mutation or recombination with field strains and experience a change in its properties. For IBV as well other coronaviruses, there is a risk of genomic mutations and recombination that may lead to emergence of new pathogenic strains. Recombination events between field strains and the Ark vaccine strain have been described Footnote 17. However, there has been no evidence of recombination between vaccine GA08 strain and field strains published so far despite widespread vaccine use in the U.S.

The risks of uncontrolled infections of pathogenic DMV strain in poultry flocks in Eastern Canada include:

  • animal welfare issues of clinical respiratory illness and mortality in affected flocks
  • economic losses in layers, broilers and broiler breeders
  • lack of competitiveness for Canadian poultry industry due to limited availability of preventative health tool
  • elevated use of antibiotics to combat secondary bacterial respiratory infections
  • emergence of new pathogenic DMV variants due to genomic mutations and recombination Footnote 18

8.2 Relative safety compared to other vaccines

Cevac IBron appears to be as safe as other live virus IB vaccines already approved for the Canadian market.

9. Mitigative measures

9.1 Worker safety

Veterinarians and workers at poultry farms responsible for vaccinating chickens might be exposed to the live attenuated vaccine organism in situations of accidental spillage or spray apparatus misdirection/malfunction. As is always the case, vaccinators should be well trained to reduce the chance of accidental exposure. For the reasons mentioned in section 5, human health concerns are not expected from accidental exposure to this vaccine organism.

9.2 Handling vaccinated or exposed animals

Veterinarians and workers at poultry farms may also be exposed to live vaccine organisms shed by vaccinated chickens, similar to other licensed IBV vaccines and field IBV strains For the reasons mentioned in section 5, human health concerns are not expected from exposure to this vaccine organism.

10. Monitoring

10.1 General

The vaccine licensing regulations in Canada require manufacturers to report all significant suspected adverse reactions to the CFIA within 15 days of receiving notice from an owner or a veterinarian. Veterinarians may also report suspected adverse reactions directly to the CFIA. If an adverse reaction complaint is received by the CCVB, the manufacturer is asked to investigate and prepare a report for the owner's veterinarian and the CFIA. If the problem is resolved to the satisfaction of the veterinarian or client, usually, no further action is requested by the CCVB. However, if the outcome of the investigation is unsatisfactory, the CCVB may initiate regulatory action, depending on the case, which may include further safety testing, temporary stoppage of product sales or product withdrawal from the market.

10.2 Human

No special monitoring of the human safety of the product will be carried out.

10.3 Animal

Veterinarians, vaccinators and producers should report any suspected adverse reactions to the CCVB as indicated previously. Suspected adverse reactions should be reported using Form CFIA/ACIA 2205 - Notification of Suspected Adverse Events to Veterinary Biologics.

11. Consultations and contacts

Manufacturer: Ceva Animal Health
8906 Rosehill Rd
Lenexa Kansas 66215
USA

12. Conclusions and actions

Based on our assessment of the available information, the CCVB has concluded that the importation and use of Bronchitis Vaccine, Georgia Type, Live Virus in Canada would not be expected to have any significant adverse effect on the environment, when manufactured and tested as described in the approved Outline of Production and used according to label directions.

Following this assessment and the completion of the Canadian veterinary biologics licensing process, the Permit to Import Veterinary Biologics held by Ceva Animal Health, Inc may be amended to allow the importation and distribution of the following products in Canada:

  • Bronchitis Vaccine, Georgia Type, Live Virus (Cevac IBron, lyophilized); CCVB File 800VV/B1.27/B10
  • Bronchitis Vaccine, Georgia Type, Live Virus (Cevac IBron, frozen); CCVB File 800VV/B1.28/B10

All serials of this product must be released by the USDA prior to importation into Canada. All conditions described in the Permit to Import Veterinary Biologics must be followed with respect to the importation and sale of this product.

13. References

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