Side Effects of the Canine DA2PP Vaccine

Each letter of the vaccine's name stands for an illness the drug prevents. The D stands for distemper, which is similar to human measles and can last for several months. The A2 stands for adenovirus-2, or hepatitis. The first P stands for parainfluenza, an upper respiratory infection that, like "kennel cough," is passed among dogs kept in close quarters. The second P stands for parvovirus, a devastating gastrointestinal disease that can be fatal within 12 to 24 hours.

Allergic reactions are less common with DA2PP than with some other types of canine vaccinations, but reactions can occur with all vaccines. Symptoms of a mild reaction to DA2PP include fever, general sluggishness and malaise, and a loss of appetite. These reactions typically appear a day or two after a shot. They tend to run their course quickly and resolve without need for further treatment. Some dogs also develop swelling at the injection site, which typically subsides in a day or two.

Urticaria, or hives, is the most common reaction dogs have to vaccines. It is an allergic skin reaction characterized by redness of the lips, around the eyes and in the neck region. It also triggers small bumps on the skin. Urticaria itself usually isn't dangerous and often clears as rapidly as it appears, but in some cases urticaria can progress to anaphylaxis, which is almost always fatal if not treated immediately.

Anaphylaxis is a severe allergic reaction that may begin with itchy or watery eyes but progresses quickly to sudden, intense symptoms such as vomiting, diarrhea, staggering, a rapid drop in blood pressure, seizures and severe swelling of the throat leading to an inability to breathe. Anaphylaxis can also trigger shock and a collapse of the cardiovascular system. Anaphylaxis must be treated immediately with epinephrine, or death is highly likely.