If the kennel owner shows proof of vaccination at the time of purchase, then there is no need to re-inject. If you are still worried, it is recommended to take the dog to the pet hospital for a check-up to see if there are antibodies in the body. If not, it should be injected. Vaccines enhance your dog’s immunity. Dogs may experience symptoms such as listlessness, lethargy, and loss of appetite before and after vaccination. This is normal and will usually recover on its own in 1-2 days.