What is it?
•Reactions from vaccines may include mild fever, muscle soreness, or lethargy
•These mild reactions are common, and they are not alarming or life-threatening
•Allergic reactions are inflammatory responses of the body to the vaccine within minutes to hours after vaccination 

What causes it?
•It is an immune reaction (response) can be directed against some vaccine component, such as infectious organism, stabilizers, preservatives, or residue from the culture
•Giving several vaccines at once increases risk for allergic reaction
•Clinical signs may include vomiting, itchy skin or bumps, swelling around the face, severe coughing, difficulty breathing, or collapse
•Symptoms usually occur within 24 hours of vaccine administration, with the most serious reactions occurring immediately
•Rarely, acute liver and kidney failure may result 

What tests are needed?
•Typically, a vaccine reaction can be diagnosed by observation of clinical signs
•Other tests may be performed to include other diseases

How is it treated?
•Again, anti-inflammatory injections can be used to halt the inflammatory cascade before it becomes too severe
•For mild reactions, anti- histamines and cortisone usually help to relieve the clinical signs
•Epinephrine may be administered for a more life-threatening reaction
•For more serious vaccine reactions, intravenous fluids and medications may be administered to restore or maintain vital signs 

What follow up care is needed?
•Ask your veterinarian regarding the administration of several vaccines at once to your pet
•Do not have your pet vaccinated at a vaccine clinic because susceptible pets may need emergency treatment if they have a vaccine reaction
•Make sure your veterinarian is aware of your pet’s susceptibility to vaccine reactions