Safety and immunogenicity in piglets of two immunization schedules initiated at two or three weeks of age with PorvacÒ, a classical swine fever subunit marker vaccine.

Classical swine fever is a highly contagious viral disease with a significant impact on food production worldwide. It currently represents one of the main limitations for the development of the pig industry in Cuba. PorvacÒ is a subunit marker vaccine that confers a very rapid onset of protection. Since there are different production systems in pig breeding, readjustments in the vaccination program are often required. This study compares the safety and efficacy in piglets of two vaccination schedules with PorvacÒ (0-2 weeks and 0-3 weeks), initiated at two or three weeks of age. Clinical monitoring was conducted, and a neutralization peroxidase-linked assay was used to measure the neutralization titers. All immunization regimens were safe and well-tolerated, without local or systemic adverse reactions in the vaccinated animals. Geometric mean neutralizing antibody titers higher than 1/1500 were detected in all groups during the six months of the trial. One month after the second immunization, piglets primed at two weeks of age, and boostered three weeks later, developed significantly higher neutralization titers (1/15644) compared to those vaccinated at a similar age but with a two-week interval between doses (1/5760). However, no significant differences in the titers were found three and six months after vaccination among the four regimens. In summary, all the variants studied are effective, but it is recommended to start vaccination at two weeks old, with the second dose at either two or three weeks later, depending on the production system and the purpose of the farm.