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My puppy had his booster today. What side effects are common?

Updated on September 23rd, 2025

Pet's info: Dog | Cocker Spaniel | Male | 11 months and 28 days old

My puppy is a year old on the 1st of sept. He has had his booster today. Will he have any side effects

1 Answer

Most Helpful Answer

Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

Published on August 29th, 2017

Well, happy early birthday to Toby. Vaccines are something that we give everyday and rarely have side effects, but side effects are certainly a possibility. The most common side effects are a mild fever, mild lethargy and discomfort at the injection site. These are the result of the vaccine stimulating the immune system and typically resolve with a day or two. More severe vaccine reactions can be analphylactic reactions and typically occur very quickly after a vaccine is given (within minutes) and may include hives, facial swelling and trouble breathing. Toby is likely already outside this time frame, so you likely do not need to worry about an anaphylactic reaction. If Toby has any signs that are abnormal after his vaccination, be sure to let your veterinarian know before he receives vaccines in the future. Please let me know if that helps. Thanks for using Petco Pet Education Center, formerly Petcoach.

1Pet Parents found this answer helpful

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