The present invention relates to a vaccine and a method for protecting piglets against PCV-2 infection by administering a vaccine comprising at least 20 micrograms/dose of ORF-2 protein of porcine circovirus type 2, even when they have a relatively high titer of maternally derived antibodies against PCV-2. A vaccine according to the invention may contain a recombinant ORF-2 protein, wherein said recombinant protein is preferably produced by way of expression from a baculovirus expression vector in insect cells, said baculovirus expression vector containing the PCV-2 ORF-2 gene sequence under control of a suitable promoter.