Is this post-vaccine symptom normal — or an emergency?
Your pet just got vaccinated and is acting unusual. Select the vaccine, enter the hours since the shot, and tap the symptoms to get an instant go/wait verdict.
Why the Hour Matters
Vaccine reactions follow predictable onset windows. The same symptom can be completely normal at 2 hours but a red flag at 48 hours.
0-2 Hours
Anaphylaxis window. Facial swelling, hives, or collapse here is an immediate emergency. Mild soreness is normal.
2-12 Hours
Mild lethargy and local soreness peak here. Vomiting once or twice can happen, but persistent vomiting requires a vet call.
12-48 Hours
Most acute reactions pass. A persistent local lump may form. Lethargy should be improving. If symptoms start now, monitor closely.
Sources & Emergency Help
This tool is deliberately caution-biased but does not replace a veterinarian. If you are unsure, call your vet.
AAHA/WSAVA guidelines: Most mild to severe adverse reactions occur within the first 12 hours post-vaccination.
Symptom tiers and timelines sourced from AAHA and WSAVA vaccination guidelines.
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