Understanding Vaccine Reactions

As with any vaccination, there are precautions and side effects associated with their use. With many vaccinations the side effects and precautions listed are those that have been compiled by the experience with these vaccines.In cases where veterinary experience is limited, human precautions and side effects have been listed. In any event, many of the side effects listed have occurred very rarely but have been included for your information and awareness. The potential benefit of the use of the vaccine must be weighed based on the risk of its use.

Your veterinarian has the best interest of your animal in mind and will help you make an informed decision about their treatment. The choice of which disease to vaccinate for is based on the risk and exposure of your animal to these diseases. Rabies vaccine is required by the state law and revaccination is yearly for animals that have only had their first vaccine and annually to triennially depending on state regulations.

Vaccines are not recommended in animals with pre existing infectious disease, fever, immunosuppression until these conditions are resolved or stabilized. Many modified live vaccines are contraindicated in pregnancy. Discuss with your veterinarian. Animals affected with Type I reactions may have low blood pressure, difficulty breathing, facial swelling, generalized hives, redness of skin, pruritus (itchiness), convulsions, pharyngeal and or laryngeal swelling, cardiac arrhythmias, vomiting and diarrhea. If severe, this type of reaction is most life threatening and can result in the death of your animal. Immediate treatment is required for severe reaction.

Type III reactions can either be local or generalized immune complex hypersensitivities. Local reactions occur at the injection site and include redness, pain, swelling, nodules or hair loss. These can occur up to a few weeks after the injection and usually resolve in a few weeks without treatment within 24 hours.

Additionally, vaccine related fibrosarcomas have been reported in cats and causality to a particular vaccine or adjuvant is still being investigated. If your animal experiences any of the above side effects contact your veterinarian.

Please discuss any questions or concerns you may have with your veterinarian.