In conclusion, if possible, veterinarians should wait at least three months after discontinuation of glucocorticoid therapy before administering vaccines, especially modified-live virus vaccines, to cats who have received high-dose, systemic glucocorticoids for more than two weeks. If continuous long-term glucocorticoid therapy is necessary, vaccination schedules should be maintained, but inactivated vaccines should be applied, if available. On the other hand, vaccination could be safely considered in well-controlled cats receiving low-dose anti-inflammatory glucocorticoid treatment. Antibody measurement against FPV infection is recommended to confirm that protection against panleukopenia is present in cats treated with glucocorticoids.