In the introduction to this review, the information is given that PCV2 is etiologically linked to several PCV-associated diseases, not only of the post-weaning period, but also to the clinical manifestations in all stages of swine production. Therefore, the previous disease name: post-weaning multisystemic wasting syndrome, PMVS, has been changed to PCV-associated diseases. Since the commercialization in 2006, the use of the vaccines against PCV2 has extended rapidly, due to the high efficacy in controlling clinical signs of PCV-associated diseases, caused not only by PCV2a, but also by the other PCV2 genotypes. However, in the last decade some concern has been raised about the protection achieved against PCV2 genotypes different from the genotype PCV2a, already present in the vaccines. This was interpreted in this paper in the following way: even if the specificity of the immunogen in the vaccine is different, it may also sufficiently protect against symptoms caused by other PCV2 genotypes, if the environmental conditions of swine production are satisfactory and if the administration of vaccine and/or vaccine preservation is appropriate. Unless these terms are not kept, then the vaccination failure takes place. Another statement of this paper corresponds to the influence of swine vaccination against PCV-AD on the expansion of variability of emerging new PCV2 genotypes.