When an intranasal Bordetella vaccine is accidentally administered subcutaneously or intramuscularly there is risk for local cellulitis, hepatotoxicity and hypersensitivity reaction – or, on the other hand, no adverse effects at all might occur.
The ASPCA Animal Poison Control Center notes that local cellulitis potentially progressing to abscess and local necrosis is the most common of adverse effects. Pain, swelling and warmth may be noted at the site of injection. If the accidental injection is caught within four hours of exposure, diluting an antibiotic in 10-30 mls of sterile saline and then infusing at the site of injection may be helpful.
If signs are already present, warm compresses and NSAIDs can be beneficial.
Hepatotoxicity is a rare but potentially serious complication of inadvertent subcutaneous or intramuscular injection of Bordetella vaccines. Oral antibiotics, liver protectants such as Sam-e, monitoring liver values and for clinical signs such as vomiting, diarrhea, lethargy and/or anorexia is advised.
Hypersensitivity reactions are rare and would be expected to respond to corticosteroids and antihistamines.
Young puppies, toy breeds, old dogs and debilitated dogs are at increased risk for reactions.