Serious adverse reactions to vaccinations include persistent vomiting or diarrhea, skin rash, swelling around the face, severe coughing, difficulty breathing, collapse and autoimmune disease. (mnn.com)
Both mild and more serious allergic reactions to a vaccination are possible. (cat-lovers-only.com)
Additionally, some pets may have negative reactions to vaccinations shortly after they are administered. (midtowngroomandboard.com)