Some cats may experience mild allergic reactions to vaccines. Allergic reactions that appear 1-2 days after vaccination may manifest as lethargy, loss of appetite, vomiting, and redness and swelling of the eyelids and eyes. These are normal immune responses and should not cause undue concern; they usually improve within two days. However, if the cat does not recover after two days, it should be taken to the vet for examination immediately. 
Precautions for cat vaccination:
1. First, deworm the cat. If the cat shows no abnormalities, then vaccinate it.
2. Generally speaking, cats need to be vaccinated with the feline triple vaccine (feline panleukopenia virus, feline herpesvirus, and feline calicivirus) and the rabies vaccine.
3. When administering a vaccine, it is necessary to ensure that the cat is in good health and has no abnormal symptoms such as fever, cough, or diarrhea.
