Pets commonly experience slight soreness and lethargy after vaccinations. Anything more serious than this should be considered a possible reaction to the vaccines and you should seek prompt medical attention. Please watch your pet carefully for any of the following signs for 48 hours after vaccinations. ** Trouble breathing ** Not eating or drinking ** Vomiting or diarrhea ** Extreme lethargy ** Swelling of face, especially around the eyes or muzzle ** Hives If you think your pet is having a vaccine reaction you should contact a local veterinarian or emergency clinic immediately. Vaccine reactions are usually mild and simply require anti-inflammatory injections. However, severe reactions can potentially be fatal.