Answer:

It is not unusual for a slight swelling to occur at the site of a vaccination. The small bump is usually a result of a localized reaction to the vaccine, and will normally subside within five-to-seven days. The bump is usually firm and remains small. If, however, the site seems to be a soft and getting larger due to swelling, or is tender, it may be an abscess. This would require a follow-up exam by your veterinarian, and he or she can advise what needs to be done, if anything. Swelling at the vaccination site is not normally a serious situation, but if there is any doubt in your mind, you should not hesitate to call your veterinarian and bring your cat in for an exam.