A comparison of two commercially available porcine reproductive and respiratory syndrome virus (PRRSV) modified-live virus vaccines analyzing the growth performance in 1-day-old vaccinated swine located on endemic farms co-circulating PRRSV-1 and PRRSV-2

Abstract

The objective of this study was to compare the efficacy of a porcine reproductive and respiratory syndrome virus (PRRSV)-1 and PRRSV-2 modified-live virus (MLV) vaccines when administered at 1 day of age under field conditions. The piglets elicited anti-PRRSV antibodies at 1 day of age even in the presence of maternally derived antibodies. The number of PRRSV-2 genomic copies in the sera of pigs from the PRRSV-2 MLV-vaccinated pigs was significantly (P<0.05) lower when compared to PRRSV-1 MLV-vaccinated pigs. The average daily gain in PRRSV-2 MLV-vaccinated pigs was significantly (P<0.05) higher when compared to both PRRSV-1 MLVvaccinated and unvaccinated pigs. This study demonstrated that vaccination as early as 1 day of age was effective against PRRSV infection.

Testable Candidate Immune Correlates of Protection for Porcine Reproductive and Respiratory Syndrome Virus Vaccination

“…Nevertheless, as we will see in our NA literature survey, NA are achievable and critical for the immune response upon challenge and for viral clearance. To begin with MLV vaccinations in farrowing and nursery-age pigs, piglets vaccinated with PRRSV MLV at one day of age with [ 83 ] or without [ 107 ] PRRSV maternal antibodies showed better performance than unvaccinated animals. In a nursery-age pig study to investigate intramuscular vs. intradermal MLV PRRSV-1 vaccination and heterologous challenge, serum NA were detectable at 21–35 days post vaccination (dpv) and continued at equivalent levels through 35 days post challenge: both vaccination methods resulted in reduced viremia and symptoms in vaccinated animals [ 108 ].…”

“…With respect to humoral immunity CoP, MLV vaccinations can generate homologous and heterologous serum NA as soon as 21 days post vaccination that provide beneficial protection during homologous challenge or environmental exposure in gilts/sows [ 75 , 76 , 80 , 107 , 118 , 119 , 165 ]. For nursery-age pigs (taking into account vaccine diversity and the number of studies), our previous discussion in Section 3.1 highlights greater variability in NA induction with multiple studies reporting NA not detectable following vaccination and lack of cross-reactivity between strains for vaccine generated NA.…”

Molecular Characteristics and Pathogenicity of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) 1 in Taiwan during 2019–2020

“…As an enveloped, positive-stranded RNA virus, PRRSV belongs to the order Nidovirales , family Arteriviridae , genus Betaarterivirus and can be classified into two species, Betaarterivirus suid 1 (PRRSV 1, formerly called the European type) and Betaarterivirus suid 2 (PRRSV 2, formerly called the North American type), with approximately 44% genetic differences between each other [ 4 , 5 ]. Both PRRSV strains manifest the same clinical signs in naïve sows and gilts [ 6 ]. In Taiwan, the first outbreak of PRRSV 2 was reported in 1993 [ 7 ].…”