Live vaccines in companion animals may pose risk to immunocompromised humans

Humans who are immunocompromised may be at risk of acquiring an infection if they are exposed to their companion animals’ live vaccines.

Researchers from Belfast, Ireland recently published a study titled, “A Doggy Tale: Risk of Zoonotic Infection with Bordetella bronchiseptica (Kennel Cough) for cystic fibrosis (CF) Patients from Live Licensed Bacterial Veterinary Vaccines for Cats and Dogs.” They reviewed vaccines for cats and dogs that could be a risk to patients with CF and identified others that are safe.

The researchers describe a situation in which a young boy was accidentally inoculated with B. bronchiseptica as his dog received the nasally administered live vaccine. The dog moved around so much that the boy was sprayed in the face with the vaccine and went on to develop a pertussis-like respiratory infection.

Patients with chronic granulomatous disease, leukocyte adhesion deficiency, myeloperoxidase deficiency, and Chediak-Higashi syndrome are also at risk because they have phagocytic function defects. This results in the inability to form reactive oxygen compounds which disrupts protein synthesis, and subsequently leads to white blood cell and bacterial dysfunction. These patients are susceptible to recurrent infections and live bacterial vaccines are contraindicated.

Most core vaccines for cats and dogs in the UK are live, attenuated. This includes the vaccine for Bordetella bronchiseptica, which is an annual vaccine. Recently, the UK licensed a dead vaccine for Bordetella bronchiseptica as a subcutaneous injectable. American vets offer Bronchicine Cae, the subcutaneously administered dead version of the Kennel Cough vaccine.

Researchers should continue to develop non-live vaccines to protect immunocompromised individuals. Veterinarians and healthcare providers must evaluate the risk to CF patients and protect them as their animals are vaccinated. They should also educate their immunocompromised pet owners on the potential infection risk when they are having their animals vaccinated with live-attenuated viral and bacterial strains.

These patients also rely on their pharmacists for vaccine advice and these words of wisdom may extend to animal vaccinations. Pharmacists should go the extra mile to stay current on veterinary innovations when it comes to vaccines.

Bella L. Bean is a 2020 PharmD candidate at the University of Connecticut in Storrs.

Reference

Moore JE, Rendall JC, Millar BC. A doggy tale: Risk of zoonotic infection with Bordetella bronchiseptica for cystic fibrosis (CF) patients from live licenced bacterial veterinary vaccines for cats and dogs [published online ahead of print, 2021 Jul 30]. J Clin Pharm Ther. 2021;10.1111/jcpt.13492. doi:10.1111/jcpt.13492