The present invention relates to a method for the treatment or prophylaxis of a PCV2 infection or for reduction of clinical symptoms caused by or associated with a PCV2 infection in animals a) having anti-PCV2 antibodies and/or b) being young piglets of 1 to 22 days of age, comprising the step of administering an effective amount of a PCV2 antigen to that animal in need of such treatment. Preferably, those animals are pigs or young piglets.